Nowhere is the intersection of western history, religion, art, and architecture as palpable as in the basilicas of Rome, the four churches in which a high altar has been set aside for use by the Pope. The oldest and most important of these is the Basilica of St. John Lateran, which is also the ecclesiastical seat of the Pope and therefore the only actual cathedral in Rome. First constructed by Constantine I in the fourth century, it was destroyed and rebuilt a number of times but still contains elements dating from Imperial times, as well as medieval, Baroque, and modern additions. The Basilica of St. Mary Major is the largest church in Rome dedicated to the Virgin. It is said to have been begun in the 4th century on a plan outlined by a miraculous August snowfall. It contains some of the oldest and most impressive apse and nave mosaics in Rome (dating from the Byzantine period and comparable with those in Ravenna). The Basilica of St. Paul Outside the Walls, the burial place of St. Paul, is outside the Roman walls and hence is less visited. It was reconstructed in the 19th century following a devastating fire and retains much of its ancient appearance. St. Peter’s Basilica, designed by Bramante, Michelangelo, and Bernini and built upon the tomb of the apostle Peter, houses Renaissance and Baroque treasures, including Michelangelo’s famous Pieta.