Today marks the anniversary of the dedication of the cathedral church of Rome, on land owned by the Laterani family, by Pope St. Sylvester I (31 Dec.), 9 Nov. 324. Honored as the episcopal seat of the pope as bishop of Rome, it is the "mother and head of all churches of Rome and the world" ("omnium ecclesiarum Urbis et Orbis mater et caput"); residence of the popes from the 4th c. until their moving to Avignon (1309); site of five ecumenical councils; dedicated to the Savior, later to John the Baptist.