Initially a Franciscan community, founded at the end of the 13th century, after the building was donated to the brothers of San Francesco al Prato. The sloped entrance is flanked by a terracotta via crucis (1633-36).
In 1754 the baroque library, designed by Pietro Carattoli, was added. Home to over 10,000 works, the Napoleonic army was the first to begin its dismantling. Well worthy of note are the cloisters and courtyards, as well as the magnificent view of the town.