Theo Thomassen holds the Chair in Archival Science at the Department of Media Studies (programmes in Archival and Information Studies) at the University of Amsterdam . He studied history at the University of Leiden (1985) and archivistics at the Dutch Archives School (1979 and 1989). He obtained his doctorate with honours at the University of Amsterdam on the basis of his thesis Instruments of Power. The States-General and their archives 1576-1796 .
Previously, Thomassen served as Director of the Reinwardt Academy , Faculty of Cultural Heritage of the Amsterdam School of The Arts, offering a higher professional education level Bachelor's programme in Cultural Heritage and an international Master's programme in Museum Studies (2002-2009). Prior tothis time, he spent fifteen years workingat the (Rijks)Archiefschool ( Dutch Archives School ), nine of which he served as Director (1990-1998). He also served as lecturer at the UvA and HvA between 1998 and 2002. He served as (vice) president of the International Council on Archives' Section on Archival Education and Training (1990-2000) and member of the Council for Culture's archival committee (2001-2005).
Thomassen devotes his tenure to teaching and research in the area of archival science. During the past decade Archival Science has developed into a broadly-oriented discipline. The current scientific focus is on the creation and maintenance of records as evidence of business functions, on the archival construction of collective memory, and on the social, cultural and political circumstances by which these processes of creation and construction are determined. In his capacity as lecturer, Thomassen is mainly involved in the Cultural Information Studies programme and Archival Science Professional Master's programme. He is also involved in harmonising the contents and organisational structure of the Archival Science programmes at the University of Amsterdam (Archivistics A), Hogeschool van Amsterdam, University of Applied Sciences (Archivistics B) and Reinwardt Academy.