The Church of St Giles was probably built as a private church by Edwin, son of Godegose, between 1123 and 1133, but soon had a huge but thinly populated parish of its own stretching northwards as far as the present northern bypass, and extending from Walton Street in the West to to the River Cherwell in the east. St John's College has held the advowson of the church since 1553.

The church was damaged during the siege of Oxford in the Civil War, and in 1643 its furniture was burnt by parliamentary troops who were being held prisoner in the church.