After Rome was sacked, Ravenna became the capital of the Western Roman Empire from 402 until 476, when the empire collapsed after being conquered by Theodoric the Great and the Ostrogoths. While Ravenna was under Gothic control, Arian patrons had embarked upon a notable building program of chapels and baptisteries in Ravenna. In 535, the city was conquered by Justinian I, who created the Exarchate of Ravenna, effectively making Ravenna the seat of Byzantine power on the Italian Peninsula. Orthodox bishops under Justinian continued and expanded the construction of basilicas to the adjacent port city of Classe, commissioning some of the finest mosaics anywhere in the world. Surviving monuments, some of which predate Exarchate, include the Basilica of San Vitale, the Archiepiscopal Chapel, the Arian Baptistry, the Neonian Baptistry, the Mausoleum of Galla Placidia, the Basilica Sant’Apollinare Nuovo, the Mausoleum of Theodoric and the Basilica of Sant'Apollinare in Classe. All eight of these monuments have been inscribed on the UNESCO World Heritage list as superb examples of early Christian mosaic art.