Over the centuries it has undergone many alterations and additions. The 12th century work survives in the east wall of the chancel wall and in the south aisle, and the altar dedicated to St Thomas Becket. The west tower was built between 1511 and 1531. The south porch, with a room above it, was also added around this time. In 1841–42, George Gilbert Scott rebuilt the chancel and the north aisle. This complemented his Martyrs’ Memorial just north of the church. It was the first Victorian Gothic interior in Oxford.
The church holds an early 14th-century carved wooden chest known as the “Jewel Chest”
