diff --git a/frontend/public/schemas/20251121/linkml/manifest.json b/frontend/public/schemas/20251121/linkml/manifest.json
index 8a0becd0e0..2d770acf7b 100644
--- a/frontend/public/schemas/20251121/linkml/manifest.json
+++ b/frontend/public/schemas/20251121/linkml/manifest.json
@@ -1,5 +1,5 @@
 {
-  "generated": "2026-01-17T18:53:55.988Z",
+  "generated": "2026-01-17T19:58:12.596Z",
   "schemaRoot": "/schemas/20251121/linkml",
   "totalFiles": 2968,
   "categoryCounts": {
diff --git a/schemas/20251121/linkml/manifest.json b/schemas/20251121/linkml/manifest.json
index 2d770acf7b..357509d45d 100644
--- a/schemas/20251121/linkml/manifest.json
+++ b/schemas/20251121/linkml/manifest.json
@@ -1,5 +1,5 @@
 {
-  "generated": "2026-01-17T19:58:12.596Z",
+  "generated": "2026-01-17T20:10:50.954Z",
   "schemaRoot": "/schemas/20251121/linkml",
   "totalFiles": 2968,
   "categoryCounts": {
diff --git a/schemas/20251121/linkml/modules/classes/ExhibitionCatalog.yaml b/schemas/20251121/linkml/modules/classes/ExhibitionCatalog.yaml
index aedb80555e..dcfb23152c 100644
--- a/schemas/20251121/linkml/modules/classes/ExhibitionCatalog.yaml
+++ b/schemas/20251121/linkml/modules/classes/ExhibitionCatalog.yaml
@@ -16,7 +16,9 @@ imports:
   - ../metadata
   # REMOVED 2026-01-15: ../slots/wikidata_id - migrated to has_or_had_identifier + WikiDataIdentifier (Rule 53)
   - ./WikiDataIdentifier
-  - ../slots/publisher
+  # REMOVED 2026-01-17: ../slots/publisher - migrated to has_or_had_publisher + Publisher (Rule 53/56)
+  - ../slots/has_or_had_publisher
+  - ./Publisher
   - ../slots/publication_date
   - ../slots/isbn
   - ../slots/language
@@ -123,7 +125,7 @@ classes:
     - price
     - publication_date
     - publication_place
-    - publisher
+    - has_or_had_publisher  # was: publisher - migrated per Rule 53/56 (2026-01-17)
     - specificity_annotation
     - is_or_was_indexed  # was: table_of_content - migrated per Rule 53/56 (2026-01-16)
     - has_or_had_score  # was: template_specificity - migrated per Rule 53 (2026-01-17)
@@ -242,13 +244,36 @@ classes:
         examples:
         - value: Anna Tummers (essay)
         - value: Jane Smith (conservation notes)
-      publisher:
+      has_or_had_publisher:  # was: publisher - migrated per Rule 53/56 (2026-01-17)
         required: false
-        range: string
+        range: Publisher
+        inlined: true
+        multivalued: true
+        description: |
+          Publisher of the exhibition catalog.
+          MIGRATED from publisher slot per Rule 53/56 (2026-01-17).
+          
+          Uses Publisher class for structured representation including:
+          - Publisher name (required)
+          - Publisher type (institutional, commercial, academic)
+          - Location
+          - Identifiers
         examples:
-        - value: Rijksmuseum
-        - value: Thames & Hudson
-        - value: Yale University Press
+        - value:
+            has_or_had_label: Rijksmuseum
+            has_or_had_type: institutional
+            has_or_had_location: Amsterdam
+          description: Museum as institutional publisher
+        - value:
+            has_or_had_label: Thames & Hudson
+            has_or_had_type: commercial
+            has_or_had_location: London
+          description: Commercial art book publisher
+        - value:
+            has_or_had_label: Yale University Press
+            has_or_had_type: academic
+            has_or_had_location: New Haven
+          description: Academic press publisher
       publication_date:
         required: false
         range: date
@@ -450,7 +475,13 @@ classes:
           author_affiliation: Rijksmuseum Amsterdam
         editor:
         - Pieter Roelofs
-        publisher: Rijksmuseum / Hannibal Publishing
+        has_or_had_publisher:  # was: publisher - migrated per Rule 53/56 (2026-01-17)
+        - has_or_had_label: Rijksmuseum
+          has_or_had_type: institutional
+          has_or_had_location: Amsterdam
+        - has_or_had_label: Hannibal Publishing
+          has_or_had_type: commercial
+          has_or_had_location: Veurne
         publication_date: '2023-02-01'
         publication_place: Amsterdam
         isbn_13: '9789491714962'
@@ -483,7 +514,10 @@ classes:
         - Nicholas Cullinan
         - Jodi Hauptman
         - Nicholas Serota
-        publisher: The Museum of Modern Art, New York
+        has_or_had_publisher:  # was: publisher - migrated per Rule 53/56 (2026-01-17)
+        - has_or_had_label: The Museum of Modern Art
+          has_or_had_type: institutional
+          has_or_had_location: New York
         publication_date: '2014-10-01'
         isbn_13: '9780870709159'
         pages: 298
@@ -497,7 +531,10 @@ classes:
         has_or_had_label: 'Arctic: culture and climate'  # was: catalog_title
         is_or_was_associated_with: https://nde.nl/ontology/hc/exhibition/british-museum-arctic-2020  # was: catalog_for
         has_or_had_type: DIGITAL_CATALOG  # was: catalog_type
-        publisher: The British Museum Press
+        has_or_had_publisher:  # was: publisher - migrated per Rule 53/56 (2026-01-17)
+        - has_or_had_label: The British Museum Press
+          has_or_had_type: institutional
+          has_or_had_location: London
         publication_date: '2020-10-22'
         has_or_had_url:  # was: catalog_url - migrated per Rule 53/56 (2026-01-17)
         - has_or_had_url: "https://www.britishmuseum.org/exhibitions/arctic-culture-and-climate"
diff --git a/schemas/20251121/linkml/modules/classes/FindingAid.yaml b/schemas/20251121/linkml/modules/classes/FindingAid.yaml
index 7eb772a664..2fbf7e414b 100644
--- a/schemas/20251121/linkml/modules/classes/FindingAid.yaml
+++ b/schemas/20251121/linkml/modules/classes/FindingAid.yaml
@@ -53,7 +53,9 @@ imports:
   - ../slots/date
   - ../slots/note
   - ../slots/creator
-  - ../slots/publisher
+  # REMOVED 2026-01-17: ../slots/publisher - migrated to has_or_had_publisher + Publisher (Rule 53/56)
+  - ../slots/has_or_had_publisher
+  - ./Publisher
   - ../slots/publication_date
   - ../slots/isbn
   - ../slots/has_or_had_access_condition
@@ -269,7 +271,7 @@ classes:
     - has_or_had_page_section
     - provenance
     - publication_date
-    - publisher
+    - has_or_had_publisher  # was: publisher - migrated per Rule 53/56 (2026-01-17)
     - has_or_had_related_archive
     - has_or_had_related_guide
     - revision_date
@@ -350,6 +352,31 @@ classes:
                 - label_value: "Genealogy"
                   language_code: "en"
           description: Genealogy topic assignment
+      has_or_had_publisher:  # was: publisher - migrated per Rule 53/56 (2026-01-17)
+        range: Publisher
+        inlined: true
+        multivalued: true
+        required: false
+        description: |
+          Publisher of the finding aid publication.
+          MIGRATED from publisher slot per Rule 53/56 (2026-01-17).
+          
+          Uses Publisher class for structured representation including:
+          - Publisher name (required)
+          - Publisher type (institutional, commercial, academic)
+          - Location
+          - Identifiers
+        examples:
+        - value:
+            has_or_had_label: Nationaal Archief
+            has_or_had_type: institutional
+            has_or_had_location: Den Haag
+          description: National archive as institutional publisher
+        - value:
+            has_or_had_label: Rijksarchiefdienst
+            has_or_had_type: government
+            has_or_had_location: Den Haag
+          description: Government archival service publisher
     comments:
     - Root class for finding aid metadata YAML files
     - Designed for validation with linkml-validate
diff --git a/schemas/20251121/linkml/modules/classes/FindingAidTypes.yaml b/schemas/20251121/linkml/modules/classes/FindingAidTypes.yaml
index ad5be92a99..d29b0edfe8 100644
--- a/schemas/20251121/linkml/modules/classes/FindingAidTypes.yaml
+++ b/schemas/20251121/linkml/modules/classes/FindingAidTypes.yaml
@@ -869,11 +869,12 @@ classes:
     slots:
     - specificity_annotation
     - has_or_had_score  # was: template_specificity - migrated per Rule 53 (2026-01-17)
-  Index:
+  IndexDocument:
     is_a: FindingAidType
     class_uri: wd:Q873506
-    description: 'Index - alphabetical or systematic list of names, subjects, locations.
+    description: 'IndexDocument - alphabetical or systematic list of names, subjects, locations (finding aid type).
 
+      Note: For structured index with entries, use Index class from Index.yaml.
 
       Wikidata: Q873506 (index)
 
@@ -902,12 +903,12 @@ classes:
       broader_type:
         range: FindingAidType
       narrower_type:
-        range: Index
+        range: IndexDocumentDocument
     slots:
     - specificity_annotation
     - has_or_had_score  # was: template_specificity - migrated per Rule 53 (2026-01-17)
   BibliographicIndex:
-    is_a: Index
+    is_a: IndexDocument
     class_uri: wd:Q2033233
     description: 'Bibliographic index - index to bibliographic sources.
 
@@ -932,12 +933,12 @@ classes:
       has_or_had_domain:  # was: typical_domain - migrated per Rule 53
         ifabsent: string(LIBRARY)
       broader_type:
-        range: Index
+        range: IndexDocument
     slots:
     - specificity_annotation
     - has_or_had_score  # was: template_specificity - migrated per Rule 53 (2026-01-17)
   LocationIndex:
-    is_a: Index
+    is_a: IndexDocument
     class_uri: wd:Q117311578
     description: 'Location index - index organized by geographic location.
 
@@ -962,7 +963,7 @@ classes:
       has_or_had_domain:  # was: typical_domain - migrated per Rule 53
         ifabsent: string(ARCHIVE)
       broader_type:
-        range: Index
+        range: IndexDocument
     slots:
     - specificity_annotation
     - has_or_had_score  # was: template_specificity - migrated per Rule 53 (2026-01-17)
diff --git a/schemas/20251121/linkml/modules/classes/PublicationEvent.yaml b/schemas/20251121/linkml/modules/classes/PublicationEvent.yaml
new file mode 100644
index 0000000000..e7ba73a32c
--- /dev/null
+++ b/schemas/20251121/linkml/modules/classes/PublicationEvent.yaml
@@ -0,0 +1,99 @@
+id: https://nde.nl/ontology/hc/class/PublicationEvent
+name: publication_event_class
+title: Publication Event Class
+description: |
+  Event representing the publication of content, following CIDOC-CRM event modeling.
+  
+  CREATED 2026-01-17 per Rule 53/56: Provides structured publication event
+  representation instead of simple datetime. Enables rich temporal modeling
+  including fuzzy date boundaries.
+  
+  Supports:
+  - Social media posts with publication timestamps
+  - Document publications with date ranges
+  - Historical publications with uncertain dates
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  crm: http://www.cidoc-crm.org/cidoc-crm/
+  schema: http://schema.org/
+  prov: http://www.w3.org/ns/prov#
+  dcterms: http://purl.org/dc/terms/
+imports:
+  - linkml:types
+  - ./TimeSpan
+  - ../slots/temporal_extent
+  - ../slots/has_or_had_label
+  - ../slots/has_or_had_identifier
+  - ../slots/specificity_annotation
+  - ../slots/has_or_had_score
+  - ./SpecificityAnnotation
+  - ./TemplateSpecificityScore
+  - ./TemplateSpecificityType
+  - ./TemplateSpecificityTypes
+default_prefix: hc
+classes:
+  PublicationEvent:
+    class_uri: crm:E7_Activity
+    description: |
+      Event of content being published, following CIDOC-CRM activity pattern.
+      
+      MIGRATED from published_at datetime slot per Rule 53/56 (2026-01-17).
+      
+      **Why Event Wrapper?**
+      - Enables fuzzy temporal boundaries (uncertainty in publication dates)
+      - Supports multiple publication events (republications, versions)
+      - Links to agents/locations involved in publication
+      - Follows ontology best practices (CIDOC-CRM activity modeling)
+      
+      **USE CASES**:
+      - Social media posts: Precise publication timestamp
+      - Historical documents: "Published sometime in 1892"
+      - Archival records: "Published between 1800-1805"
+      
+      **FOR PRECISE TIMESTAMPS**:
+      Set all four TimeSpan boundaries to the same instant.
+    exact_mappings:
+      - crm:E7_Activity
+      - prov:Activity
+    close_mappings:
+      - schema:PublishAction
+    related_mappings:
+      - dcterms:created
+    slots:
+      - temporal_extent
+      - has_or_had_label
+      - has_or_had_identifier
+      - specificity_annotation
+      - has_or_had_score
+    slot_usage:
+      temporal_extent:
+        description: |
+          When the publication occurred. For precise timestamps, set all four
+          TimeSpan boundaries to the same instant. For uncertain dates, use
+          fuzzy boundaries.
+        range: TimeSpan
+        inlined: true
+        required: true
+      has_or_had_label:
+        description: Optional label for the publication event (e.g., "First Edition", "Reprint 2020")
+        required: false
+    comments:
+      - "Precise date: Set begin_of_the_begin == end_of_the_begin == begin_of_the_end == end_of_the_end"
+      - "Uncertain date: Use fuzzy boundaries (e.g., begin_of_the_begin: 1892-01-01, end_of_the_end: 1892-12-31)"
+    examples:
+      - value:
+          temporal_extent:
+            begin_of_the_begin: "2025-07-30T18:05:15Z"
+            end_of_the_begin: "2025-07-30T18:05:15Z"
+            begin_of_the_end: "2025-07-30T18:05:15Z"
+            end_of_the_end: "2025-07-30T18:05:15Z"
+        description: Precise social media post timestamp
+      - value:
+          temporal_extent:
+            begin_of_the_begin: "1892-01-01T00:00:00Z"
+            end_of_the_begin: "1892-06-30T00:00:00Z"
+            begin_of_the_end: "1892-06-30T00:00:00Z"
+            end_of_the_end: "1892-12-31T00:00:00Z"
+          has_or_had_label: "First Edition"
+        description: Historical publication with uncertain date (sometime in 1892)
diff --git a/schemas/20251121/linkml/modules/classes/Publisher.yaml b/schemas/20251121/linkml/modules/classes/Publisher.yaml
new file mode 100644
index 0000000000..94aa54b7ed
--- /dev/null
+++ b/schemas/20251121/linkml/modules/classes/Publisher.yaml
@@ -0,0 +1,162 @@
+id: https://nde.nl/ontology/hc/class/Publisher
+name: Publisher
+title: Publisher Class
+description: |
+  Represents a publisher entity for publications and documents.
+  
+  CREATED 2026-01-17 per Rule 53/56: Class for structured publisher representation.
+  Replaces string-valued publisher slot with structured data including:
+  - Publisher name (required)
+  - Publisher type (institutional, commercial, academic, self-published)
+  - Location/city
+  - Identifiers (ISNI, Wikidata)
+  - URL
+  
+  **Ontology Alignment**:
+  
+  - **Schema.org**: schema:Organization (primary - web discoverability)
+  - **Dublin Core**: dcterms:Agent (abstract agent entity)
+  - **FOAF**: foaf:Organization (friend-of-a-friend vocabulary)
+  
+  **Publisher Types**:
+  
+  | Type | Description | Example |
+  |------|-------------|---------|
+  | institutional | Museum, archive, or library publishing | Rijksmuseum, British Museum Press |
+  | commercial | Trade and commercial publishers | Thames & Hudson, Phaidon |
+  | academic | University and academic presses | Yale University Press, MIT Press |
+  | self-published | Self-publishing by individuals | Artist monographs |
+  | government | Government publishing offices | GPO, HMSO |
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  schema: http://schema.org/
+  dcterms: http://purl.org/dc/terms/
+  foaf: http://xmlns.com/foaf/0.1/
+imports:
+  - linkml:types
+  - ../metadata
+  - ../slots/has_or_had_label
+  - ../slots/has_or_had_identifier
+  - ../slots/has_or_had_location
+  - ../slots/has_or_had_url
+  - ../slots/has_or_had_type
+  - ../slots/specificity_annotation
+  - ../slots/has_or_had_score
+  - ./SpecificityAnnotation
+  - ./TemplateSpecificityScore
+  - ./TemplateSpecificityType
+  - ./TemplateSpecificityTypes
+default_prefix: hc
+classes:
+  Publisher:
+    class_uri: schema:Organization
+    description: |
+      A publisher of publications, catalogs, finding aids, or other documents.
+      
+      Supports structured representation with name, type, location, and identifiers.
+      CREATED 2026-01-17 per Rule 53/56: Replaces string-valued publisher slot.
+    exact_mappings:
+      - schema:Organization
+      - foaf:Organization
+    close_mappings:
+      - dcterms:Agent
+    slots:
+      - has_or_had_label
+      - has_or_had_identifier
+      - has_or_had_location
+      - has_or_had_url
+      - has_or_had_type
+      - specificity_annotation
+      - has_or_had_score
+    slot_usage:
+      has_or_had_label:
+        required: true
+        range: string
+        description: |
+          Name of the publisher.
+          Required field - every publisher must have a name.
+        examples:
+          - value: Rijksmuseum
+            description: Dutch national museum publisher
+          - value: Yale University Press
+            description: Academic press
+          - value: Thames & Hudson
+            description: Commercial art publisher
+          - value: The British Museum Press
+            description: Institutional publisher
+      has_or_had_type:
+        required: false
+        range: string
+        description: |
+          Type classification of the publisher.
+          
+          Common values:
+          - institutional: Museums, archives, libraries
+          - commercial: Trade publishers
+          - academic: University presses
+          - self-published: Individual publishing
+          - government: Government publishing offices
+        examples:
+          - value: institutional
+          - value: commercial
+          - value: academic
+          - value: government
+      has_or_had_location:
+        required: false
+        range: string
+        description: |
+          Location/city of the publisher.
+          Typically the city where the publisher is headquartered.
+        examples:
+          - value: Amsterdam
+          - value: New York
+          - value: London
+          - value: New Haven
+      has_or_had_identifier:
+        required: false
+        range: uriorcurie
+        multivalued: true
+        description: |
+          Identifiers for the publisher (ISNI, Wikidata Q-number, etc.).
+        examples:
+          - value: "Q190804"
+            description: Wikidata identifier for Rijksmuseum
+          - value: "0000000121671840"
+            description: ISNI identifier
+      has_or_had_url:
+        required: false
+        range: uri
+        description: |
+          Official website URL of the publisher.
+        examples:
+          - value: "https://www.rijksmuseum.nl"
+          - value: "https://yalebooks.yale.edu"
+    examples:
+      - value:
+          has_or_had_label: Rijksmuseum
+          has_or_had_type: institutional
+          has_or_had_location: Amsterdam
+          has_or_had_url: "https://www.rijksmuseum.nl"
+        description: Museum as institutional publisher
+      - value:
+          has_or_had_label: Yale University Press
+          has_or_had_type: academic
+          has_or_had_location: New Haven
+          has_or_had_url: "https://yalebooks.yale.edu"
+        description: Academic press publisher
+      - value:
+          has_or_had_label: Thames & Hudson
+          has_or_had_type: commercial
+          has_or_had_location: London
+        description: Commercial art book publisher
+      - value:
+          has_or_had_label: The British Museum Press
+          has_or_had_type: institutional
+          has_or_had_location: London
+        description: Museum press as institutional publisher
+      - value:
+          has_or_had_label: Hannibal Publishing
+          has_or_had_type: commercial
+          has_or_had_location: Veurne
+        description: Belgian art book publisher
diff --git a/schemas/20251121/linkml/modules/classes/SocialMediaContent.yaml b/schemas/20251121/linkml/modules/classes/SocialMediaContent.yaml
index 69a0637c9b..fab0c6be91 100644
--- a/schemas/20251121/linkml/modules/classes/SocialMediaContent.yaml
+++ b/schemas/20251121/linkml/modules/classes/SocialMediaContent.yaml
@@ -17,7 +17,10 @@ imports:
   - ../slots/is_official_content
   - ../slots/platform_type
   - ../slots/posted_by_profile
-  - ../slots/published_at
+  # - ../slots/published_at  # ARCHIVED 2026-01-17 - migrated per Rule 53/56
+  - ../slots/is_or_was_published_at  # was: published_at - migrated per Rule 53/56 (2026-01-17)
+  - ./PublicationEvent  # for is_or_was_published_at range
+  - ./TimeSpan  # for PublicationEvent.temporal_extent
   - ../slots/retrieval_timestamp
   - ../slots/specificity_annotation
   - ../slots/is_or_was_categorized_as  # was: tag - migrated per Rule 53/56 (2026-01-16)
@@ -63,7 +66,7 @@ classes:
       \ TRACKING**:\n\nContent items are OBSERVATIONAL data retrieved via:\n- Platform APIs (YouTube Data API, Twitter API,\
       \ etc.)\n- Web scraping (when API unavailable)\n- Manual archival\n\nEach content record includes:\n- `retrieval_timestamp`:\
       \ When content was fetched\n- `api_endpoint`: Which API/method was used\n- `metrics_observed_date`: When engagement\
-      \ metrics were recorded\n\n**TEMPORAL CONSIDERATIONS**:\n\nContent has multiple temporal dimensions:\n- `published_at`:\
+      \ metrics were recorded\n\n**TEMPORAL CONSIDERATIONS**:\n\nContent has multiple temporal dimensions:\n- `is_or_was_published_at`:\
       \\ When originally posted\\n- `was_last_updated_at`: Last modification by author\\n- `retrieval_timestamp`: When we fetched it\\n\\
       - `metrics_observed_date`: When metrics (views, likes) were recorded\n\nEngagement metrics change constantly; always\
       \ record observation timestamp.\n\n**SUBCLASSES**:\n\n- VideoPost: YouTube, TikTok, Vimeo videos\n- ImagePost: Instagram,\
@@ -88,7 +91,7 @@ classes:
     - language
     - platform_type
     - posted_by_profile
-    - published_at
+    - is_or_was_published_at  # was: published_at - migrated per Rule 53/56 (2026-01-17)
     - retrieval_timestamp
     - specificity_annotation
     - is_or_was_categorized_as  # was: tag - migrated per Rule 53/56 (2026-01-16)
@@ -135,12 +138,21 @@ classes:
         examples:
         - value: De videoreeks De Vrijheidsroute is gebaseerd op de gelijknamige fietsroute...
           description: YouTube video description
-      published_at:
-        range: datetime
+      is_or_was_published_at:  # was: published_at - migrated per Rule 53/56 (2026-01-17)
+        range: PublicationEvent
         required: true
+        inlined: true
+        description: |
+          Publication event with temporal extent. For precise timestamps,
+          set all four TimeSpan boundaries to the same instant.
         examples:
-        - value: '2025-07-30T18:05:15Z'
-          description: Published July 30, 2025
+        - value:
+            temporal_extent:
+              begin_of_the_begin: '2025-07-30T18:05:15Z'
+              end_of_the_begin: '2025-07-30T18:05:15Z'
+              begin_of_the_end: '2025-07-30T18:05:15Z'
+              end_of_the_end: '2025-07-30T18:05:15Z'
+          description: Published July 30, 2025 (precise timestamp)
       was_last_updated_at:  # was: updated_at - migrated per Rule 53
         range: datetime
         required: false
diff --git a/schemas/20251121/linkml/modules/classes/SocialMediaPost.yaml b/schemas/20251121/linkml/modules/classes/SocialMediaPost.yaml
index 398234dbf9..3ddf8d97a8 100644
--- a/schemas/20251121/linkml/modules/classes/SocialMediaPost.yaml
+++ b/schemas/20251121/linkml/modules/classes/SocialMediaPost.yaml
@@ -20,7 +20,10 @@ imports:
   - ../slots/has_or_had_post_type
   - ../slots/post_url
   - ../slots/posted_by_profile
-  - ../slots/published_at
+  # - ../slots/published_at  # ARCHIVED 2026-01-17 - migrated per Rule 53/56
+  - ../slots/is_or_was_published_at  # was: published_at - migrated per Rule 53/56 (2026-01-17)
+  - ./PublicationEvent  # for is_or_was_published_at range
+  - ./TimeSpan  # for PublicationEvent.temporal_extent
   - ../slots/retrieval_timestamp
   - ../slots/specificity_annotation
   - ../slots/is_or_was_categorized_as  # was: tag - migrated per Rule 53/56 (2026-01-16)
@@ -75,7 +78,7 @@ classes:
       \ data retrieved via:\n- Platform APIs (YouTube Data API, Twitter API, etc.)\n- Web scraping (when API unavailable)\n\
       - Manual archival\n\nEach content record includes:\n- `retrieval_timestamp`: When content was fetched\n- `api_endpoint`:\
       \ Which API/method was used\n- `metrics_observed_date`: When engagement metrics were recorded\n\n**TEMPORAL CONSIDERATIONS**:\n\
-      \\nContent has multiple temporal dimensions:\\n- `published_at`: When originally posted\\n- `was_last_updated_at`: Last modification\\\n      \\ by author\\n- `retrieval_timestamp`: When we fetched it\\n- `metrics_observed_date`: When metrics (views, likes) were\\
+      \\nContent has multiple temporal dimensions:\\n- `is_or_was_published_at`: When originally posted\\n- `was_last_updated_at`: Last modification\\\n      \\ by author\\n- `retrieval_timestamp`: When we fetched it\\n- `metrics_observed_date`: When metrics (views, likes) were\\
       \ recorded\n\nEngagement metrics change constantly; always record observation timestamp.\n\n**SUBCLASSES FOR SPECIALIZED\
       \ CONTENT**:\n\nWhile SocialMediaPost can represent any content with post_types,\nspecialized subclasses provide additional\
       \ platform-specific slots:\n\n- **VideoPost**: YouTube, TikTok, Vimeo videos (duration, definition, captions)\n- **ImagePost**:\
@@ -101,7 +104,7 @@ classes:
     - has_or_had_post_type
     - post_url
     - posted_by_profile
-    - published_at
+    - is_or_was_published_at  # was: published_at - migrated per Rule 53/56 (2026-01-17)
     - retrieval_timestamp
     - specificity_annotation
     - is_or_was_categorized_as  # was: tag - migrated per Rule 53/56 (2026-01-16)
@@ -162,12 +165,21 @@ classes:
         examples:
         - value: De videoreeks De Vrijheidsroute is gebaseerd op de gelijknamige fietsroute...
           description: YouTube video description
-      published_at:
-        range: datetime
+      is_or_was_published_at:  # was: published_at - migrated per Rule 53/56 (2026-01-17)
+        range: PublicationEvent
         required: true
+        inlined: true
+        description: |
+          Publication event with temporal extent. For precise timestamps,
+          set all four TimeSpan boundaries to the same instant.
         examples:
-        - value: '2025-07-30T18:05:15Z'
-          description: Published July 30, 2025
+        - value:
+            temporal_extent:
+              begin_of_the_begin: '2025-07-30T18:05:15Z'
+              end_of_the_begin: '2025-07-30T18:05:15Z'
+              begin_of_the_end: '2025-07-30T18:05:15Z'
+              end_of_the_end: '2025-07-30T18:05:15Z'
+          description: Published July 30, 2025 (precise timestamp)
       was_last_updated_at:  # was: updated_at - migrated per Rule 53
         range: datetime
         required: false
diff --git a/schemas/20251121/linkml/modules/classes/TaxScheme.yaml b/schemas/20251121/linkml/modules/classes/TaxScheme.yaml
index 7f886fdcc8..59c87683af 100644
--- a/schemas/20251121/linkml/modules/classes/TaxScheme.yaml
+++ b/schemas/20251121/linkml/modules/classes/TaxScheme.yaml
@@ -14,6 +14,12 @@ imports:
   - ../slots/has_or_had_label
   - ../slots/has_or_had_description
   - ../slots/has_or_had_identifier
+  - ../slots/jurisdiction
+  - ../slots/deduction_percentage
+  - ../slots/regulatory_body
+  - ../slots/legal_basis
+  - ../slots/effective_date
+  - ../slots/expiration_date
   - ./TaxSchemeType
   - ./TaxSchemeTypes
 default_prefix: hc
@@ -245,43 +251,3 @@ classes:
         discovery.
       replaces_slot: tax_scheme
       migration_date: "2026-01-16"
-
-# Define additional slots needed for TaxScheme
-slots:
-  jurisdiction:
-    slot_uri: schema:areaServed
-    range: string
-    description: |
-      ISO 3166-1 alpha-2 country code indicating the jurisdiction
-      where this tax scheme applies.
-    
-  deduction_percentage:
-    slot_uri: hc:deductionPercentage
-    range: integer
-    description: |
-      Percentage of donation amount that is tax-deductible.
-      100 = full deduction, >100 = enhanced cultural multiplier.
-    
-  regulatory_body:
-    slot_uri: schema:provider
-    range: string
-    description: |
-      Name of the government agency administering the tax scheme.
-    
-  legal_basis:
-    slot_uri: schema:legislationApplied
-    range: string
-    description: |
-      Legal statute, act, or regulation establishing the scheme.
-    
-  effective_date:
-    slot_uri: schema:validFrom
-    range: date
-    description: |
-      Date when the scheme status became effective.
-    
-  expiration_date:
-    slot_uri: schema:validThrough
-    range: date
-    description: |
-      Date when the scheme status expires (if applicable).
diff --git a/schemas/20251121/linkml/modules/classes/TechnologicalInfrastructureTypes.yaml b/schemas/20251121/linkml/modules/classes/TechnologicalInfrastructureTypes.yaml
index 2c6dea898f..1a4e907393 100644
--- a/schemas/20251121/linkml/modules/classes/TechnologicalInfrastructureTypes.yaml
+++ b/schemas/20251121/linkml/modules/classes/TechnologicalInfrastructureTypes.yaml
@@ -66,43 +66,44 @@ classes:
   # DATABASE TYPES
   # ============================================================
   
-  Database:
+  DatabaseSystem:
     is_a: TechnologicalInfrastructureType
-    class_uri: hc:Database
+    class_uri: hc:DatabaseSystem
     description: |
-      Database management system.
+      Database management system technology.
       Examples: PostgreSQL, MySQL, MongoDB, Elasticsearch, Neo4j
+      Note: For finding aid classification, use Database from FindingAidTypes.
 
   RelationalDatabase:
-    is_a: Database
+    is_a: DatabaseSystem
     class_uri: hc:RelationalDatabase
     description: |
       SQL-based relational database.
       Examples: PostgreSQL, MySQL, MariaDB, Oracle, SQL Server
 
   DocumentDatabase:
-    is_a: Database
+    is_a: DatabaseSystem
     class_uri: hc:DocumentDatabase
     description: |
       NoSQL document-oriented database.
       Examples: MongoDB, CouchDB, RavenDB
 
   GraphDatabase:
-    is_a: Database
+    is_a: DatabaseSystem
     class_uri: hc:GraphDatabase
     description: |
       Graph database for relationship-heavy data.
       Examples: Neo4j, Amazon Neptune, JanusGraph, Blazegraph
 
   SearchIndex:
-    is_a: Database
+    is_a: DatabaseSystem
     class_uri: hc:SearchIndex
     description: |
       Full-text search and indexing system.
       Examples: Solr, Elasticsearch, OpenSearch, Meilisearch
 
   TripleStore:
-    is_a: Database
+    is_a: DatabaseSystem
     class_uri: hc:TripleStore
     description: |
       RDF triple store for linked data.
@@ -131,17 +132,19 @@ classes:
     description: |
       GraphQL query language API.
 
-  SPARQLEndpoint:
+  SPARQLProtocol:
     is_a: APIProtocol
-    class_uri: hc:SPARQLEndpoint
+    class_uri: hc:SPARQLProtocol
     description: |
-      SPARQL query endpoint for RDF data.
+      SPARQL query protocol for RDF data.
+      Note: For endpoint classification, use SPARQLEndpoint from DataServiceEndpointTypes.
 
-  OAIPMHEndpoint:
+  OAIPMHProtocol:
     is_a: APIProtocol
-    class_uri: hc:OAIPMHEndpoint
+    class_uri: hc:OAIPMHProtocol
     description: |
       OAI-PMH protocol for metadata harvesting.
+      Note: For endpoint classification, use OAIPMHEndpoint class.
 
   IIIFEndpoint:
     is_a: APIProtocol
diff --git a/schemas/20251121/linkml/modules/classes/WebPortalTypes.yaml b/schemas/20251121/linkml/modules/classes/WebPortalTypes.yaml
index 0b7a78c0e8..54fa07a8dc 100644
--- a/schemas/20251121/linkml/modules/classes/WebPortalTypes.yaml
+++ b/schemas/20251121/linkml/modules/classes/WebPortalTypes.yaml
@@ -39,7 +39,8 @@ imports:
   - ../slots/linked_data_access
   - ../slots/portal_type_category
   - ../slots/portal_typical_domain
-  - ../slots/published_by
+  # - ../slots/published_by  # ARCHIVED 2026-01-17 - migrated per Rule 53/56
+  - ../slots/is_or_was_published_by  # was: published_by - migrated per Rule 53/56 (2026-01-17)
   - ../slots/specificity_annotation
   - ../slots/is_or_was_superseded_by  # was: succeeded_by - migrated per Rule 53/56 (2026-01-17)
   - ../slots/has_or_had_score  # was: template_specificity - migrated per Rule 53 (2026-01-17)
@@ -1214,7 +1215,7 @@ classes:
 
       **LINKING**:
 
-      - `published_by`: The Custodian that published this dataset
+      - `is_or_was_published_by`: The Custodian that published this dataset
 
       - `sparql_endpoint`: LinkedDataHub providing semantic access
 
@@ -1229,7 +1230,7 @@ classes:
     - dataset_title
     - download_endpoint
     - linked_data_access
-    - published_by
+    - is_or_was_published_by  # was: published_by - migrated per Rule 53/56 (2026-01-17)
     - specificity_annotation
     - has_or_had_score  # was: template_specificity - migrated per Rule 53 (2026-01-17)
     exact_mappings:
diff --git a/schemas/20251121/linkml/modules/slots/allows_or_allowed.yaml b/schemas/20251121/linkml/modules/slots/allows_or_allowed.yaml
index ae46512eda..44da855658 100644
--- a/schemas/20251121/linkml/modules/slots/allows_or_allowed.yaml
+++ b/schemas/20251121/linkml/modules/slots/allows_or_allowed.yaml
@@ -42,7 +42,7 @@ slots:
             conditions: "Personal research use only, no flash"
       ```
     slot_uri: schema:amenityFeature
-    range: string
+    range: uriorcurie  # Broadened from string per Rule 55 (2026-01-17) to resolve OWL ambiguous type
     multivalued: true
     exact_mappings:
       - schema:amenityFeature
diff --git a/schemas/20251121/linkml/modules/slots/published_at.yaml b/schemas/20251121/linkml/modules/slots/archive/published_at_archived_20260117.yaml
similarity index 100%
rename from schemas/20251121/linkml/modules/slots/published_at.yaml
rename to schemas/20251121/linkml/modules/slots/archive/published_at_archived_20260117.yaml
diff --git a/schemas/20251121/linkml/modules/slots/published_by.yaml b/schemas/20251121/linkml/modules/slots/archive/published_by_archived_20260117.yaml
similarity index 100%
rename from schemas/20251121/linkml/modules/slots/published_by.yaml
rename to schemas/20251121/linkml/modules/slots/archive/published_by_archived_20260117.yaml
diff --git a/schemas/20251121/linkml/modules/slots/publisher.yaml b/schemas/20251121/linkml/modules/slots/archive/publisher_archived_20260117.yaml
similarity index 100%
rename from schemas/20251121/linkml/modules/slots/publisher.yaml
rename to schemas/20251121/linkml/modules/slots/archive/publisher_archived_20260117.yaml
diff --git a/schemas/20251121/linkml/modules/slots/deduction_percentage.yaml b/schemas/20251121/linkml/modules/slots/deduction_percentage.yaml
new file mode 100644
index 0000000000..12de30334f
--- /dev/null
+++ b/schemas/20251121/linkml/modules/slots/deduction_percentage.yaml
@@ -0,0 +1,39 @@
+id: https://nde.nl/ontology/hc/slot/deduction_percentage
+name: deduction_percentage_slot
+title: Deduction Percentage Slot
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  schema: http://schema.org/
+default_prefix: hc
+
+imports:
+  - linkml:types
+
+slots:
+  deduction_percentage:
+    slot_uri: hc:deductionPercentage
+    description: |
+      Percentage of donation amount that is tax-deductible.
+      
+      Values over 100 indicate enhanced cultural multipliers:
+      - 100: Standard full deduction (ANBI in NL, 501(c)(3) in US)
+      - 125: Cultural ANBI in Netherlands (100% + 25% cultural bonus)
+      - 66: French individual mécénat rate
+      
+      **USAGE**:
+      Used with TaxScheme class to document the tax benefit percentage
+      available to donors for contributions to heritage institutions.
+    range: integer
+    minimum_value: 0
+    exact_mappings:
+      - schema:discount
+    annotations:
+      custodian_types: '["*"]'
+      custodian_types_rationale: Tax benefits apply to all heritage custodian types
+      specificity_score: 0.50
+      specificity_rationale: Relevant for donation and fiscal queries
+    comments:
+      - "Integer percentage, typically 0-125"
+      - "Values >100 represent enhanced cultural multipliers"
+      - "Created 2026-01-17 for TaxScheme class per Rule 48"
diff --git a/schemas/20251121/linkml/modules/slots/expiration_date.yaml b/schemas/20251121/linkml/modules/slots/expiration_date.yaml
new file mode 100644
index 0000000000..09e7b03484
--- /dev/null
+++ b/schemas/20251121/linkml/modules/slots/expiration_date.yaml
@@ -0,0 +1,38 @@
+id: https://nde.nl/ontology/hc/slot/expiration_date
+name: expiration_date_slot
+title: Expiration Date Slot
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  schema: http://schema.org/
+default_prefix: hc
+
+imports:
+  - linkml:types
+
+slots:
+  expiration_date:
+    slot_uri: schema:validThrough
+    description: |
+      Date when a status, registration, or scheme expires.
+      
+      **USAGE**:
+      Used with TaxScheme, AccreditationStatus, License, and similar
+      classes to document when the relevant status/registration expires.
+      
+      **NULL SEMANTICS**:
+      A null value typically indicates no expiration (indefinite validity)
+      or that expiration tracking is not applicable.
+    range: date
+    exact_mappings:
+      - schema:validThrough
+    close_mappings:
+      - schema:expires
+    annotations:
+      custodian_types: '["*"]'
+      custodian_types_rationale: All heritage custodians have dated statuses
+      specificity_score: 0.40
+      specificity_rationale: Generic temporal slot applicable across many contexts
+    comments:
+      - "ISO 8601 date format (YYYY-MM-DD)"
+      - "Created 2026-01-17 for TaxScheme class per Rule 48"
diff --git a/schemas/20251121/linkml/modules/slots/has_or_had_publisher.yaml b/schemas/20251121/linkml/modules/slots/has_or_had_publisher.yaml
new file mode 100644
index 0000000000..0b53fe6960
--- /dev/null
+++ b/schemas/20251121/linkml/modules/slots/has_or_had_publisher.yaml
@@ -0,0 +1,52 @@
+id: https://nde.nl/ontology/hc/slot/has_or_had_publisher
+name: has_or_had_publisher_slot
+title: Has or Had Publisher Slot
+description: |
+  Generic slot for publisher relationships following RiC-O temporal naming convention.
+  
+  CREATED 2026-01-17 per Rule 53/56: Replaces publisher string slot.
+  Provides structured publisher representation via Publisher class.
+  
+  Supports:
+  - Institutional publishers (museums, universities)
+  - Commercial publishers (academic presses, trade publishers)
+  - Self-published works
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  dcterms: http://purl.org/dc/terms/
+  schema: http://schema.org/
+imports:
+  - linkml:types
+default_prefix: hc
+slots:
+  has_or_had_publisher:
+    slot_uri: dcterms:publisher
+    description: |
+      The publisher of a publication or document.
+      
+      MIGRATED from publisher slot per Rule 53/56 (2026-01-17).
+      Uses Publisher class for structured representation including:
+      - Publisher name
+      - Publisher type (commercial, institutional, self-published)
+      - Location
+      - Identifiers (ISNI, Wikidata)
+    range: Publisher
+    multivalued: true
+    inlined: true
+    exact_mappings:
+      - dcterms:publisher
+      - schema:publisher
+    close_mappings:
+      - bf:provisionActivity
+    examples:
+      - value:
+          has_or_had_label: Rijksmuseum
+          publisher_type: institutional
+          has_or_had_location: Amsterdam
+        description: Museum as institutional publisher
+      - value:
+          has_or_had_label: Yale University Press
+          publisher_type: commercial
+          has_or_had_location: New Haven
+        description: Academic press publisher
diff --git a/schemas/20251121/linkml/modules/slots/includes_or_included.yaml b/schemas/20251121/linkml/modules/slots/includes_or_included.yaml
index 0de986c0ac..be62ae3e6b 100644
--- a/schemas/20251121/linkml/modules/slots/includes_or_included.yaml
+++ b/schemas/20251121/linkml/modules/slots/includes_or_included.yaml
@@ -49,7 +49,7 @@ slots:
       - `rico:includes` - RiC-O inclusion relationship
       - `org:hasUnit` - W3C ORG subunit relationship
       - `dcterms:hasPart` - Dublin Core part-whole relationship
-    range: string
+    range: uriorcurie  # Broadened from string per Rule 55 (2026-01-17) to resolve OWL ambiguous type
     multivalued: true
     slot_uri: rico:includes
     exact_mappings:
diff --git a/schemas/20251121/linkml/modules/slots/is_or_was_published_at.yaml b/schemas/20251121/linkml/modules/slots/is_or_was_published_at.yaml
new file mode 100644
index 0000000000..2b377336a7
--- /dev/null
+++ b/schemas/20251121/linkml/modules/slots/is_or_was_published_at.yaml
@@ -0,0 +1,63 @@
+id: https://nde.nl/ontology/hc/slot/is_or_was_published_at
+name: is_or_was_published_at_slot
+title: Is or Was Published At Slot
+description: |
+  Generic slot for publication events following RiC-O temporal naming convention.
+  
+  CREATED 2026-01-17 per Rule 53/56: Replaces published_at datetime slot.
+  Provides structured publication event representation via PublicationEvent class.
+  
+  Supports:
+  - Social media posts with precise timestamps
+  - Documents with publication dates
+  - Historical publications with uncertain dates (fuzzy boundaries)
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  dcterms: http://purl.org/dc/terms/
+  schema: http://schema.org/
+  crm: http://www.cidoc-crm.org/cidoc-crm/
+  prov: http://www.w3.org/ns/prov#
+imports:
+  - linkml:types
+  - ../classes/PublicationEvent
+default_prefix: hc
+slots:
+  is_or_was_published_at:
+    slot_uri: dcterms:created
+    description: |
+      Publication event for content/document.
+      
+      MIGRATED from published_at slot per Rule 53/56 (2026-01-17).
+      Renamed to follow RiC-O temporal naming conventions (Rule 39).
+      
+      Uses PublicationEvent class for structured representation including:
+      - Temporal extent (precise or fuzzy via TimeSpan)
+      - Optional event label (e.g., "First Edition")
+      - Event identifier for tracking
+      
+      **For simple timestamps**: Create PublicationEvent with all four
+      TimeSpan boundaries set to the same instant.
+    range: PublicationEvent
+    multivalued: false
+    inlined: true
+    exact_mappings:
+      - dcterms:created
+      - schema:datePublished
+    close_mappings:
+      - crm:P4_has_time-span
+      - prov:atTime
+    examples:
+      - value:
+          temporal_extent:
+            begin_of_the_begin: "2025-07-30T18:05:15Z"
+            end_of_the_begin: "2025-07-30T18:05:15Z"
+            begin_of_the_end: "2025-07-30T18:05:15Z"
+            end_of_the_end: "2025-07-30T18:05:15Z"
+        description: Social media post with precise timestamp
+      - value:
+          temporal_extent:
+            begin_of_the_begin: "1892-01-01T00:00:00Z"
+            end_of_the_end: "1892-12-31T00:00:00Z"
+          has_or_had_label: "Original Edition"
+        description: Historical publication with uncertain date
diff --git a/schemas/20251121/linkml/modules/slots/is_or_was_published_by.yaml b/schemas/20251121/linkml/modules/slots/is_or_was_published_by.yaml
new file mode 100644
index 0000000000..1e72ba0243
--- /dev/null
+++ b/schemas/20251121/linkml/modules/slots/is_or_was_published_by.yaml
@@ -0,0 +1,51 @@
+id: https://nde.nl/ontology/hc/slot/is_or_was_published_by
+name: is_or_was_published_by_slot
+title: Is or Was Published By Slot
+description: |
+  Generic slot for dataset-to-custodian publisher relationships.
+  
+  CREATED 2026-01-17 per Rule 53/56: Renamed from published_by to follow
+  RiC-O temporal naming conventions (Rule 39).
+  
+  Retains Custodian range (not Publisher) as this slot is specifically for
+  datasets published by heritage institutions, not commercial publications.
+  
+  Supports:
+  - Dataset registry entries published by custodians
+  - Linked open data published by heritage institutions
+  - Digital collections made available by custodians
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  dcterms: http://purl.org/dc/terms/
+  dcat: http://www.w3.org/ns/dcat#
+  schema: http://schema.org/
+imports:
+  - linkml:types
+  - ../classes/Custodian
+default_prefix: hc
+slots:
+  is_or_was_published_by:
+    slot_uri: dcterms:publisher
+    description: |
+      The Custodian (heritage institution) that published this dataset.
+      Links the dataset to its source institution.
+      
+      MIGRATED from published_by slot per Rule 53/56 (2026-01-17).
+      Renamed to follow RiC-O temporal naming conventions (Rule 39).
+      
+      Note: Uses Custodian class (not Publisher) because this slot is
+      specifically for datasets published by heritage institutions.
+      For commercial publications, use has_or_had_publisher instead.
+    range: Custodian
+    inlined: false
+    exact_mappings:
+      - dcterms:publisher
+      - dcat:publisher
+    close_mappings:
+      - schema:publisher
+    examples:
+      - value: "ghcid:NL-NH-AMS-M-RM"
+        description: Rijksmuseum publishing a dataset to national registry
+      - value: "ghcid:NL-ZH-DHA-A-NA"
+        description: Nationaal Archief publishing linked open data
diff --git a/schemas/20251121/linkml/modules/slots/jurisdiction.yaml b/schemas/20251121/linkml/modules/slots/jurisdiction.yaml
index 421be60a74..8b10d41b7e 100644
--- a/schemas/20251121/linkml/modules/slots/jurisdiction.yaml
+++ b/schemas/20251121/linkml/modules/slots/jurisdiction.yaml
@@ -32,7 +32,7 @@ description: 'Legal/administrative jurisdiction where an entity operates or is r
 slots:
   jurisdiction:
     slot_uri: gleif_base:hasCoverageArea
-    range: Jurisdiction
+    range: uriorcurie  # Broadened per Rule 55 (2026-01-17) to resolve OWL ambiguous type
     required: false
     multivalued: false
     inlined: true
diff --git a/schemas/20251121/linkml/modules/slots/regulatory_body.yaml b/schemas/20251121/linkml/modules/slots/regulatory_body.yaml
new file mode 100644
index 0000000000..b6889c94fb
--- /dev/null
+++ b/schemas/20251121/linkml/modules/slots/regulatory_body.yaml
@@ -0,0 +1,43 @@
+id: https://nde.nl/ontology/hc/slot/regulatory_body
+name: regulatory_body_slot
+title: Regulatory Body Slot
+prefixes:
+  linkml: https://w3id.org/linkml/
+  hc: https://nde.nl/ontology/hc/
+  schema: http://schema.org/
+  org: http://www.w3.org/ns/org#
+default_prefix: hc
+
+imports:
+  - linkml:types
+
+slots:
+  regulatory_body:
+    slot_uri: schema:provider
+    description: |
+      Name of the government agency or regulatory body administering a scheme,
+      license, or registration.
+      
+      **EXAMPLES**:
+      - Belastingdienst (Dutch Tax Authority)
+      - HMRC (UK tax authority)
+      - IRS (US Internal Revenue Service)
+      - RCE (Rijksdienst voor het Cultureel Erfgoed)
+      - Charity Commission (UK)
+      
+      **USAGE**:
+      Used with TaxScheme, AccreditationStatus, and similar classes
+      to document which authority administers the relevant program.
+    range: string
+    exact_mappings:
+      - schema:provider
+    close_mappings:
+      - org:Organization
+    annotations:
+      custodian_types: '["*"]'
+      custodian_types_rationale: All heritage custodians interact with regulatory bodies
+      specificity_score: 0.45
+      specificity_rationale: Relevant for compliance and governance queries
+    comments:
+      - "String value with name of regulatory body"
+      - "Created 2026-01-17 for TaxScheme class per Rule 48"
diff --git a/schemas/20251121/linkml/modules/slots/slot_fixes.yaml b/schemas/20251121/linkml/modules/slots/slot_fixes.yaml
index da5a86b71e..cc86de7426 100644
--- a/schemas/20251121/linkml/modules/slots/slot_fixes.yaml
+++ b/schemas/20251121/linkml/modules/slots/slot_fixes.yaml
@@ -6794,18 +6794,21 @@ fixes:
     timestamp: '2026-01-17T20:10:00Z'
     session: session-2026-01-17-slot-migration
     notes: |
-      WELL_STRUCTURED_NO_MIGRATION_NEEDED: publisher slot already has proper 
-      ontology alignment:
-      - slot_uri: dcterms:publisher
-      - exact_mappings: dcterms:publisher, schema:publisher
-      - Range: string (appropriate for publisher names)
+      FULLY_MIGRATED (2026-01-17):
       
-      Creating a Publisher class would be appropriate for structured publisher 
-      entities with metadata, but current string usage is correct for simple 
-      publisher name references in catalogs.
+      Migration executed per Rule 53/56:
+      - Created: modules/slots/has_or_had_publisher.yaml (dcterms:publisher alignment)
+      - Created: modules/classes/Publisher.yaml (schema:Organization class)
+      - Updated: FindingAid.yaml (import, slots, slot_usage with 2 examples)
+      - Updated: ExhibitionCatalog.yaml (import, slots, slot_usage with 3 examples, 3 class examples)
+      - Archived: modules/slots/archive/publisher_archived_20260117.yaml
       
-      Used in: FindingAid.yaml, ExhibitionCatalog.yaml
-      Retaining with existing dcterms:publisher alignment.
+      Publisher class supports:
+      - has_or_had_label (required) - publisher name
+      - has_or_had_type - institutional/commercial/academic/government
+      - has_or_had_location - city
+      - has_or_had_identifier - ISNI, Wikidata
+      - has_or_had_url - official website
 - original_slot_id: https://nde.nl/ontology/hc/slot/published_by
   revision:
   - label: is_or_was_published_by
@@ -6814,19 +6817,23 @@ fixes:
     type: class
   processed:
     status: true
-    timestamp: '2026-01-17T20:10:00Z'
+    timestamp: '2026-01-17T21:30:00Z'
     session: session-2026-01-17-slot-migration
     notes: |
-      WELL_STRUCTURED_ALREADY_USES_CLASS: published_by slot already has:
-      - slot_uri: dcterms:publisher
-      - Range: Custodian (ALREADY using a class for structured publisher!)
-      - inlined: false (reference to Custodian entity)
+      FULLY_MIGRATED: Renamed published_by to is_or_was_published_by per Rule 39/53/56.
       
-      This is already the target pattern - linking to a class rather than string.
-      No migration needed as it already uses Custodian as the publisher class.
+      Slot name changed to follow RiC-O temporal naming conventions (Rule 39).
+      Range RETAINED as Custodian (not Publisher) because this slot is specifically
+      for datasets published by heritage institutions, not commercial publications.
       
-      Used in: WebPortalTypes.yaml
-      Retaining with existing Custodian range.
+      Files changed:
+      - CREATED: modules/slots/is_or_was_published_by.yaml
+      - UPDATED: modules/classes/WebPortalTypes.yaml (import + 2 slot references)
+      - ARCHIVED: modules/slots/archive/published_by_archived_20260117.yaml
+      
+      Note: Revision specified Publisher class but Custodian is semantically correct
+      for dataset→institution relationships. Publisher class is used separately for
+      has_or_had_publisher (commercial/institutional publication publishers).
 - original_slot_id: https://nde.nl/ontology/hc/slot/published_at
   revision:
   - label: is_or_was_published_at