The basilica, dedicated to St John the Baptist (with whom St John the Apostle is now associated), stands on the site of a palace which belonged to the family of the Laterani. The palace, given to the Church by Constantine, was the official residence of the Popes from the 4th cent. until they went to Avignon (1309). It was mostly destroyed by fire in 1308. The new palace, which was at one time a museum of antiquities, now houses the offices of the diocese of Rome. The present church was built under a succession of Popes beginning with Urban V. It is the cathedral church of Rome.