Since the late Middle Ages there has been a collection of books for services and studies in the Cathedral of Strängnäs. In the 17th century the book collection was essentially enlarged through gifts and purchases. Queen Christina donated a part of the literary war trophy from the Thirty Years War to the cathedral. The library is a European cultural treasure with late medieval manuscripts and prints from the 1460ies to the beginning of the 18th century. There are 4 000 printed books of which about 600 are incunables (books printed before 1501). Dominating subjects are theology, philosophy, canon law and history. The books are written in 15 different languages, most of them in Latin or German. With this project the collection will be accessible for research. A new catalogue of prints will be drawn up. Besides author, title and printer it also will contain facts about provenance and description of the binding. The catalogue is recorded digitally and will be accessible through the online catalogue LIBRIS. The cataloguing is accomplished in consultation with The Royal Library in Stockholm. The project is also financed by funds from The Royal Academy of Letters, History and Antiquities and the Church of Sweden.