About Ars Accordia

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: 202 artwork passports from the Klasiskais modernisms collection, covering Latvian modernist painting from the early 20th century. Authority records for 287 Latvian artists with links to Wikidata, Getty ULAN, and VIAF.

Each work receives an Artwork Passport — a standards-based, authoritative identity document analogous to a museum catalogue entry. A complete passport records:

• Identity — title, creator, date, medium, dimensions, object type (CDWA)
• Authority links — verified connections to Wikidata, Getty ULAN, Getty AAT, ICONCLASS, VIAF, and other international registries
• Provenance — chain of ownership with dates and sources
• Condition — documented state at time of cataloguing
• Structured data — Schema.org JSON-LD for search engines and aggregators
• Export formats — LIDO 1.1 and EODEM XML for museum exchange

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:

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:

• Artwork Passports: AP-YYYY-NNNNNN (e.g. AP-2026-000001)
• Artist records: ART-NAME-YYYY

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.

Secure the record. Know exactly what you hold, prove it is yours, and be ready for whatever comes. That is what a documented collection gives its owner first — and everything below is how.

Art data sits on a deep stack of standards. Look closely and they do four things well — and one thing only in fragments.

The five layers of an artwork's record

1. Describe it — CDWA · Object ID — the fields a complete record needs.
2. Classify its concepts — Getty AAT — type, medium, and technique as controlled terms.
3. Identify its people — Getty ULAN · VIAF · Wikidata — the artist, the sitter, and the owners and collectors who held it.
4. Move and expose the record — LIDO · EODEM · Schema.org — so it reaches museums, aggregators, lenders, insurers, and search.
5. Anchor the object itself — give this individual work a stable identity others can point to, so it can be found, cited, and recognised as the same object across every record that mentions it. In practice: connect it to whatever object-level identifiers exist — an institutional inventory number, a museum API record, a catalogue reference, a IIIF manifest, a Europeana or Wikidata artwork item — and mint one where none does.

Layers one through four are well served. The fifth is fragmented — and it fails in the ordinary case, not only the rare one. Most artworks have no public identity as objects at all. You can usually identify the artist — link them to ULAN, to Wikidata, in minutes — but the work itself connects to nothing: it lives as a photograph and a description in a private file, indexed by no public record, indistinguishable from a copy or a sibling version except to whoever holds it. Often the attribution itself is unsettled — "circle of," "attributed to," "Danish school" — and the object floats freer still. The pattern holds all the way up: a portrait whose painter is catalogued and whose sitter was an empress can still link, as an object, to nothing.

The gap is not that art is hard to describe. It is that the individual work is hard to point to.

The standards describe, classify, identify, and move art. Ars Accordia anchors the object — connecting the work to the institutional and public records that name it, and minting the anchor where none exists. We give the individual work a permanent Artwork Passport and connect it to the anchors that already hold it: a museum object number, an inventory record, a catalogue reference, a Wikidata artwork item. Where the anchor exists, we preserve it and make it visible. Where the public record is missing and the sources support it, we contribute it back. Where none exists at all, the passport itself becomes the stable starting point — a cited, reviewable object identity others can rely on.

Why it matters. A work nobody can properly identify is hard to insure, hard to pass on, hard to sell or lend. A documented one isn't. These are the moments that test a collection — inheritance, insurance, a sale, a division among heirs, a donation, a loan — and at each of them, the difference is whether the record exists. We don't change what a work is worth. We make it straightforward to deal with when the time comes.

We do not replace museums, catalogues, or authority files; we connect them at the level where the gap is most often felt — the individual object. And we do not judge, authenticate, or value the work ourselves. The contribution is the object anchor; the liquidity is what it earns.

The long-term mission 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 invisible to scholarship. We believe museum-grade standards should not be reserved for public institutions.

Ars Accordia operates across three distinct intellectual property layers, each governed by different rights:

To report a copyright concern, contact catalogue@arsaccordia.com.

If you hold works of art in a private or corporate collection that are undocumented, insufficiently anchored, or facing a transition — an inheritance, an insurance review, a potential sale or division — 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 anchored against international standards, assigned a permanent Artwork Passport ID, and published in the registry with your chosen visibility level (public, restricted, or private). The result is a collection with a complete, usable record: documented, verifiable, and straightforward to deal with at the moments that matter.

• Corporate art collections — boardroom, office, and hospitality holdings
• Private collections — inherited or acquired works needing documentation
• Estate cataloguing — documentation for succession, insurance, and transfer
• Institutional collections — foundations, law firms, banks, universities

To enquire about cataloguing your collection, contact: catalogue@arsaccordia.com