The Basilica di San Pietro di Castello, known as San Pietro di Castello, is a Roman Catholic minor basilica in Venice's Castello sestiere. The current building dates to the 16th century, though a church has stood on the site since at least the 7th century. St. Magnus, Bishop of Oderzo, founded the church in early Venice, establishing a significant religious center. From 1451 to 1807, it served as Venice's cathedral, though it never held the same importance as St. Mark’s Basilica, which became the city’s state church.
Over the years, the church underwent several alterations and additions. In the 16th century, Andrea Palladio received his first commission in Venice to redesign the church’s facade and interior. However, the project faced delays due to Patriarch Vincenzo Diedo’s death before completion. As St. Mark’s Basilica gained more attention, San Pietro's importance diminished, leading to its gradual decline. During World War I, the church suffered firebomb damage and fell into further disrepair.
In the 1970s, conservation groups began restoring the church. Today, these efforts continue through the Chorus Association of Venetian Churches, which helps manage its preservation. The church remains located on San Pietro di Castello, a small island at the eastern end of Venice. Though overshadowed by other landmarks, it remains an essential historical and religious site in the city.