Methodology · Standards · Mission
Ars Accordia is a scholarly cataloguing service for European art collections — corporate, private, and institutional. It brings each work to international museum documentation standards. It is not a marketplace, a CRM, or a gallery platform. Its sole purpose is rigorous identification, documentation, and permanent registration of works of art.
The catalogue serves as a public registry for art held in private and corporate collections that does not appear in national museum catalogues or on Europeana. This fills a significant gap in the European cultural heritage record: thousands of works held outside public institutions that are undocumented, unstandardised, and invisible to scholarship.
Current catalogue contents: The two published passports include the Mona Lisa (a standards demonstration record — included to show the full capability of the format against a universally known work) and a painting by Herberts Siliņš (a privately held work, representing the intended subject of the registry). The artist index of ~288 Latvian painters is seed data used for authority-reconciliation work; those artists will be matched to private holdings as collections are onboarded.
Each work receives an Artwork Passport — a standards-based, authoritative identity document analogous to a museum catalogue entry. A complete passport records:
Passports are human-readable (HTML), machine-readable (Schema.org, LIDO 1.1 / EODEM XML), and permanently identified. Once issued, an Artwork Passport ID is never reused or reassigned.
Current catalogue state: Passports currently published capture identity, authority links, and structured data (Schema.org JSON-LD). Provenance, condition, and LIDO/EODEM XML export are part of the full specification and are being progressively completed as records are reviewed. Individual passports indicate their completeness status.
Every catalogue record is produced in compliance with internationally recognised museum documentation standards:
| Standard | What it does | Where used |
|---|---|---|
| Object ID | ICOM nine-category minimum identification | Every artwork record |
| CDWA | Cataloguing rules for art (J. Paul Getty Trust) | House style, field structure |
| LIDO 1.1 | XML exchange format for cultural objects | Export pipeline |
| EODEM | LIDO profile for museum loans (ICOM-CC) | Export pipeline |
| Getty AAT | Controlled vocabulary for object types & materials | Artwork records |
| Getty ULAN | Union List of Artist Names authority | Artist records |
| Getty TGN | Thesaurus of Geographic Names | Provenance & place records |
| ICONCLASS | Iconographic subject classification | Subject records |
| Wikidata | Cross-reference hub for all entities | Artist & artwork records |
| VIAF | Virtual International Authority File (artists) | Artist records |
| ISNI / ORCID / RKD | Additional artist authority identifiers | Artist records |
| Schema.org | Structured data for web discovery | Every page (JSON-LD) |
Every artist and artwork record carries a four-grade corroboration level modelled on the GLEIF Legal Entity Identifier standard:
| Badge | Level | Meaning |
|---|---|---|
| Green | Fully Corroborated | All identity fields confirmed by a citable authority (Wikidata, ULAN, VIAF, RKD, etc.) and reviewed by a human cataloguer. |
| Amber | Partially Corroborated | Some identity fields are confirmed by citable authority, or all fields are confirmed but only by the automated pipeline (not yet reviewed by a human). |
| Grey | Entity-Supplied Only | Data comes only from non-citable sources (commercial gallery, owner assertion). No independent authority corroboration yet. |
| – | Pending | Record is under review and has not yet been assessed. |
Level 1 covers identity (name, dates, nationality). Level 2 covers relationships and provenance. Both levels are evaluated independently and displayed on every artist record. The badge displayed on artist pages reflects Level 1.
Catalogue data flows through a transparent pipeline:
Every export run is committed as a Git version, creating an immutable audit trail of all catalogue changes. This provides the same versioning guarantee as a museum collection management system, without the infrastructure cost.
Every entity in the catalogue receives a stable identifier that is never reused, never reassigned:
Passport IDs form stable URLs at arsaccordia.com/AP-YYYY-NNNNNN.html.
These URLs are permanent and will never be redirected away without a canonical replacement being
issued first.
The long-term mission of Ars Accordia is to become the reference registry for European art held in private and corporate collections — art that is culturally significant but currently undocumented, unavailable to researchers, and unprotected against loss, theft, or misattribution.
We believe that scholarly standards should not be reserved for public museums. A work of art deserves the same rigour of identification whether it hangs in a national gallery or a corporate boardroom. Ars Accordia brings museum-grade documentation practice to private collections at scale.
If you hold works of art in a private or corporate collection that are undocumented, unstandardised, or invisible to scholarship — Ars Accordia exists for exactly this purpose.
Cataloguing begins with a consultation to assess your collection's scope and documentation needs. Each work is then catalogued against international standards, assigned a permanent Artwork Passport ID, and published in the registry with your chosen visibility level (public, restricted, or private).
To enquire about cataloguing your collection, contact: catalogue@arsaccordia.com