The collection on the history of the Reformation forms the outstanding core of the Gotha Research Library. The extensive handwritten and printed records, which were mainly collected by the ducal house of Saxe-Gotha-Altenburg at Friedenstein Palace between 1640 and 1825, have been and are being made known to researchers and the interested public in a variety of projects by the Gotha Research Library. The library is thus increasingly developing into a centre for source-based Protestantism research.