The earliest datable stonework in the church today is the fine Norman arch of the south door, with its zig-zag pattern overlapping a round moulding, some dogs-tooth work and columns with carved capitals. The style of the doorway suggests a late twelfth-century date.
The lead-lined font-bowl in the nave may also be of this period.
Virtually the entire church was rebuilt, at least from waist height, in the 13th century, probably using the original limestone rubble. The Gothic chancel arch was inserted at this time, and the chancel itself enlarged to its present size, with the piscina and a tall lancet window (the lower part of which was subsequently blocked) inserted in the south wall. The trussed rafter roof in the chancel may also date from this time, as such roofs are rare in churches after 1400. The bell-cote is also 13th century. Lancets were inserted in the west and south walls and a door, now blocked but which may have led to monastic buildings, in the north wall. The porch was also added as part of this 13th century rebuilding.
In the 14th or 15th centuries, further windows were added in both nave and chancel. Those in the west and south walls of the nave consist of pairs of trefoiled windows, with deep internal splaying and wooden lintels, within a rectangular frame. They are earlier than the more elaborate 15th century Perpendicular Gothic cinquefoil three-light east and south windows in the chancel. The tie-beam nave roof was also raised about 2 ft above the original corbels as part of this work. The roof itself is of stone slates, possibly from Stonesfield, which began production about this time. Other work possibly carried out at this time was the buttressing of the chancel, probably to ensure that the roof structure (which was not renewed or strengthened with tie-beams) could support the stone slates.