San Giovanni in Laterano (St John Lateran), one of the city's four major basilicas, is the official seat of the Pope in his capacity as Bishop of Rome. Founded by Constantine, the basilica was totally rebuilt during the Baroque period and then again in the 18C. Galilei's façade leads into a rather cold and solemn interior in which the hallmark of Borromini and followers of Bernini can be seen. The Romanesque cloister with its use of Ancient Roman marble is one of Vassalletto's finest works. The Museo della Basilica houses the cathedral's treasure.