In recent decades, our collective memory has been digitised by institutions, citizens, and associations. This digitisation is considered key to transforming cultural heritage into new knowledge resources. Once the digital heritage is made visible and searchable, culture truly becomes usable. Large sets of data, which are compatible and open for new services and knowledge sharing, are also enabling the creation of new businesses that are already highlighting the added value inherent in digital cultural heritage.

For this reason, the European Union lists digitisation of cultural heritage among its priorities in the field. The Commission’s new strategic framework “Culture Compass” (2025) introduces a dual mandate for the cultural sector: fostering “Europe for Culture” through social cohesion and “Culture for Europe” through economic competitiveness. This strategic vision is technically manifested in a new digital ecosystem for cultural heritage comprised of three infrastructures forming a nexus for digital cultural heritage: the European Collaborative Cloud for Cultural Heritage (ECCCH), the Common European Data Space for Cultural Heritage, and the European Open Science Cloud (EOSC).

While the EOSC pushes for open science and data re-use in other sectors, Data Space for Cultural Heritage is a form designed to support multi-layered ecosystems, in which data sovereignty is one of the key concepts, as opposed to platformisation, where all data is concentrated and held in the hands of private companies whose interest is to exploit data for commercial purposes. Additionally, the ECCCH imposes a cloud-based architecture as the primary means for institutional cooperation.

This paper argues that while these infrastructures aim for technical interoperability, they represent a significant governance challenge regarding the balance between “open science” and “data sovereignty”. By examining the power dynamics of digital ownership, I pose a critical question: Who owns the data in this emerging ecosystem for digital cultural heritage, and how are cultural heritage institutions being reshaped by these infrastructures?

To address this, the research employs a theoretical framework combining media archaeology and mediatisation theory. Rather than viewing these infrastructures as neutral, a media archaeological lens allows us to “excavate” the governance blueprints and technical standards of the nexus. I argue that the push for AI-readability and high-volume data exchange in the Data Space embeds a “technological logic” that favours standardised, economically viable data over non-standardised cultural resources. Furthermore, through the lens of mediatisation, I analyse how heritage institutions are forced to adapt their behaviours to the “platform logic” of the European clouds.

Finally, this paper demonstrates how policy-driven technological choices dictate the future of cultural memory, determining whether heritage institutions remain guardians of a “public good” or become providers for a commercialised data market.