San Pietro sits on the island of Olivolo which was the Easternmost part of the city until the creation of Sant'Elena. A church of 650, one of the 12 established by St Magnus, was dedicated to Saints Sergius and Bacchus, but was replaced and enlarged from 774 to 841 with one dedicated to Saint Peter. It was part of a bishop's residence until 1451 when it became the home of the Venetian patriarch. Following restoration work in 1120 and 1506-1522, patriarch Vincenzo Diedo commissioned Palladio in 1556 with the church’s rebuilding.