Tresoar came into being in 2002 as the new Frisian Historical and Literary Centre following the merger of three institutions: the Rijksarchief (Public Records Office), the Provinciale en Buma Bibliotheek van Friesland/PBF (Provincial and Buma Library of Friesland) and the Frysk Letterkundich Museum en Dokumintaasjesintrum/FLMD (Frisian Literature Museum and Documentation Centre). The new institute functions as records office, library, documentation centre and museum. This means supporting the research of the Frisian language and literature as well as the history of Friesland by collecting and conserving relevant material and making it available to the public.

Tresoar’s library department also serves as a storage facility for printed matter (books, magazines, newspapers etc) originating from or dealing with the province of Friesland. Within the national framework of the Wetenschappelijke Steunfunctie/WSF (Scientific Support Function), the library also provides supplementary public library facilities. Finally, Tresoar plays an important educational and museological role with regard to the Frisian culture.