Slightly later in the 13th century the south chapel was added, and the easternmost arch of the south aisle became the entrance to the chapel. Three of the chapel's windows are round-headed 13th-century late Norman ones: two in the east wall and one in the south wall. The chapel is taller than the nave, so that on the south side of the clerestory the more easterly windows now look into the chapel instead of outside. The 13th century may also be the period when the church was given a west tower.