St. Victor's Monastery was built in the fifth century A. D. on the ruins of the ancient city. It has been situated on the South Bank of the old port. After several ruins, the monastery was reinforced under Pope Urban V of the 14th century. The monastery's Cathedral under the city contains important cultural relics of the fifth century A.D. and many sarcophagus left behind at that time. It contains the remains of many Christians and pagans. Two of the oldest martyr skeletons are buried in the tomb, which is the remains of the monastery when it was first built. It was from this monastery that the Christianization process began throughout Provence.