Netherlands
Allard Pierson / Library of the University of Amsterdam
Theatre Collection
https://theatercollectie.uva.nl/
In 2012, the collection of the Theater Instituut Nederland was transferred to the university library. This brought materials from all theater and dance genres since the seventeenth century into the custody of the Allard Pierson. It involves more than half a million objects: from masks and costumes to puppets, posters, models and miniature theaters.
Music Collection
https://uba.uva.nl/en/search-the-collection/start-your-search/start-your-search.html
The music collection ranges from sheet music from the seventeenth century to digital streams from the twenty-first century and includes classical and contemporary composed music alongside pop, jazz and improvised music.
Circus Heritage
The circus collection was added in 1963 and is composed of private collections from collectors and institutions that have stored circus heritage over the centuries. The collection consists of posters, programs, photographs, slides, flyers, clippings and other documentation of circus performances. See
Theaterencyclopedia
https://theaterencyclopedie.nl/
The encyclopedia on Dutch theater history includes a database of approximately 90,000 performances played in the Netherlands since 1751. At the same time, the encyclopedia is based on the Wikipedia principle: anyone can register to add their own information.