Otto I's military protection of Pietro IV ensured his hold over power in Venice despite his autocratic tendencies over the republican city. In 973, however, Otto I died. With Otto II busy suppressing revolts in Germany, the Venetians opposed to Pietro IV found their opportunity to depose him. Imprisoning the Doge within his palace, the Venetian nobles set fire to the building. However, the fire soon spread to Saint Mark's Basilica, resulting in the greater part of the city being burnt. The Doge and his son, also named Pietro, were killed in the blaze, but their bodies were later recovered and respectfully buried. Pietro IV's younger son, Vitale Candiano, survived, however, and fled to Otto II's court in Saxony with plans to depose the new pro-Byzantine Doge, Pietro I Orseolo.