Much of the tomb contents and decorations have been lost since the building's conversion to a military fortress in 401 and its subsequent inclusion in the Aurelian Walls by Flavius Honorius Augustus. The urns and ashes were scattered by Visigoth looters during Alaric's sacking of Rome in 410, and the original decorative bronze and stone statuary were thrown down upon the attacking Goths when they besieged Rome in 537, as recounted by Procopius. An unusual survivor, however, is the capstone of a funerary urn (probably that of Hadrian), which made its way to Saint Peter's Basilica, covered the tomb of Otto II and later was incorporated into a massive Renaissance baptistery. The use of spolia from the tomb in the post-Roman period was noted in the 16th century – Giorgio Vasari writes: