Wikimedia CEE Meeting 2025/Learning Day/Report

Group photo in the afternoon of the Learning Day

The Learning Day is an event that took place in 25 September 2025, one day before the opening ceremony of the Wikimedia CEE Meeting 2025, the 14th edition of the Wikimedia CEE Meeting. It was hosted on the Goethe-Institut in Thessaloniki.

The Wikimedia CEE Meeting is the annual conference for the Wikimedians of the CEE region. Learning Day is an annual preconference event of CEE Meeting and covers issues important to Wikimedians, such as conflict prevention, organising, governance and others.

This year, Christos Varvantakis organised it on behalf of the Wikimedia CEE Meeting 2025 organising committee, and the program was focused on Wikidata, Wikibase and the interconnected nature of structured data, library data and Wikidata.

Introductory session

Christos Varvantakis, lead organiser of the event.

In the opening session of the Learning Day, Christos thanked the Greek organising team for the invitation that was extended to him. He also introduced the two main speakers Camillo Pellizzari and Alan Ang, and gave practical instructions about what is going to happen in the Learning Day.

Morning sessions

Speakers Camillo Pellizzari and Alan Ang during the session of Alan about Wikidata.

Alan began by speaking about the common mission of Goethe and the Wikimedia movement. He introduced Wikidata to the attendees. He then talked about the use of Wikidata and how Wikidata is the next generation of cataloging, as well as how it is extremely important for every librarian. He also explained that it is important for more organizations to participate in Wikidata by adding data.

Camillo Pellizzari began his morning session by explaining the authority files that libraries maintain, while emphasizing in the fact that many people do not know their importance. He also mentioned the various activities that have been organised in Italy around Wikidata, including an event that he organised in Italy, catered to librarians, that was quite successful. He also explained what is an authority record, that shows the information about the books that a library has in its collection. He gave an example from Leo Tolstoy, and how properly created authority files and structures allow finding the work of a particular author from homonyms (i.e. two or more authors with the same name). He explained the mechanisms of the cataloging of the books' information by libraries.

Camillo Pellizzari speaking on the Learning Day.

Furthermore Camillo also explained the aims of the authority record and what the databases VIAF and ISNI are doing. He also showed how Wikidata can be useful to libraries and how they can enrich it with data from the authority files they maintain, and how the libraries can gain from Wikidata and the tools that it offers. He also showed the situation of libraries in Europe and urged Wikipedians in Central and Eastern Europe to cooperate with libraries on recording their databases in Wikidata.

Afternoon sessions

Mārite Apenīte and Uldis Bojārs, speakers during the use cases session.

The morning session that Camillo led lasted until 12:00. A break then took place from 12:00 to 13:30.

After the midday break, representatives from three national libraries of the CEE region talked about use cases of Wikibase and Wikidata in their institutions.

Mārite Apenīte and Uldis Bojārs from the National Library of Latvia (NLL) talked about how they are integrating Wikidata for the recording of NLL's library data, the challenges they face to record the library data and authority files to Wikidata. They also presented the system with which they record data in the Latvian language.

After the presentation that the Latvian representatives delivered, a Greek librarian, Michail Gerolimos was next. Gerolimos represented the National Library of Greece. He explained the work that the National Library of Greece is doing, the importance of RDA resources and how Wikibase is being used to improve their databases of authority and bibliographic records.

Also, Petra Šťastná, from the National Library of Czech Republic led a presentation during the afternoon session block which covered the Czech National Authority File, it's content, interoperability between Czech libraries and it's uses. Šťastná also talked about the increasing release of CNAF's contents as open, freely licensed data and the collaboration between the National Library of Czech Republic and Wikimedia Czech Republic to record the library data on Wikidata and release contents of the library to Wikimedia project.

Hands on session

After the completion of the sessions that showed the experiences from the application of Wikibase and Wikidata by libraries, the Learning Day was completed with a two-hour session (lasting from 15:30 to 17:30) led by Camillo Pellizzari, which allowed the participants to practically apply what they learned in the session. Among others, they added VIAF records and statements missing on Wikidata items about authors from their countries, using information from the Wikidata gadget QLever and the Query Service to find authors where these statements were missing.

Links to presentation slides

• Wikidata and library authority files (Wikimedia CEE Meeting 2025, Learning Day) by Camillo Pellizzari
• National Thesaurus Data on Wikidata – Case Study of the National Library of Latvia by Mārite Apenīte and Uldis Bojārs
• Czech National Authority File overview, by Petra Šťastná
• From MARC21 to Linked Data. Implementing Wikibase and RDA-RDF by Michail Gerolimos