A church belonging to the Norman St. Wandrille's Abbey stood here in 1086 and was served by a clerk. It is reasonable to assume that there was a Saxon church that was replaced by a Norman one in the 12th century. The chancel is from the 12th century and by the middle of that century a rector had been presented and a priory established, which remained until 1378. It was apparently a poor priory with only a small farm and few livestock. When alien orders were expelled from England there were only three monks at Upavon in 1378. The nave, with north and south aisles, is 13th century while the west tower was built in the late 13th century. By 1299 a vicarage was ordained and by 1308 the church was dedicated to St. Mary. Windows in the north aisle were replaced and a north porch built in the 14th century. However by the late 14th and early 15th centuries the chancel was said to be in disrepair and there was bird droppings on the altar owing to holes in the roof; in 1411 it was stated that the church was ruinous. This probably came about through a succession of absentee vicars while the removal of the priory could have been a contributory factor. During the 15th century the chancel was repaired and the nave and aisles re-roofed. The chancel was also provided with a new east window. Problems in the 16th century included a violent and drunken vicar, no registers kept and no quarterly sermons given.