The library of the Certosa, which now forms part of the National Monument of Trisulti, is today housed in the Palace of Innocent III and the ‘Palazzo della Meridiana’. In 1204 Innocent gave the monastery to the Carthusians as well as the church dedicated to St Bartholomew which had been built in the Ernici mountains by the community of Benedictines who had gathered round the hermit Domenico da Foligno. A new charterhouse was built, with its own pharmacy, scriptorium, and a large library. It was an important landowner and was also granted many privileges and other benefits. The monks dedicated their time to work and study. A series of priors at the head of the charterhouse between the 16th and 19th centuries succeeded in preserving its patrimony as well as promoting new building and cultural renewal as well as the study of the monastery’s archival and library collections.