CIDOC-CRM

Available

 * http://www.cidoc-crm.org/

Description
From the official website (accessed 2019-10-14):

The CIDOC Conceptual Reference Model (CRM) provides definitions and a formal structure for describing the implicit and explicit concepts and relationships used in cultural heritage documentation.

Other ontological models based on CIDOC-CRM have been developed for specific domains: for example, CRMtex, created in 2015, models concepts related to the study of ancient texts, and POGO (Philology-Oriented Graphematics Ontology) regards the graphematic/alphabetic representation of text in primary sources.