In the churchyard immediately overlooking what is now Church Street stands a medieval preaching cross, and the knoll may have been a site of worship in Saxon times, but the first building which we know to have stood on this site was erected shortly after the Norman Conquest and may have included the earliest extant part of the church – the blocked up door on the south side of the nave.

The door with its round Norman arch may have been the original entrance to the church since church doors were traditionally on the south side and at that stage much of the village may have been in the area to the south of the church which is now an orchard. The outline of the nave and perhaps some of the lower stonework probably go back to the twelfth century, and the round piers to the arches to the north aisle are transitional between Norman and Early English style. (The arches themselves, however, are double chamfered, a typical fourteenth century feature).

The North Aisle was added sometime around 1200 and the Chancel about a hundred years later. The fourteenth century saw not only the creation of the Gothic arches between the Nave and the North Aisle but also the building of the Tower and the Porch. Here ironstone was used rather than the local limestone. Somerton is close to the geological border between limestone and ironstone country, and the ironstone, though more expensive was probably thought to be superior, but a very white limestone was used to good effect for the Crucifixion depicted on the North side of the Tower.

A south aisle was also added in the fourteenth century. This was much extended and altered in the sixteenth and seventeenth century to accommodate the memorials to the Fermor family.

The fifteenth century saw further works not to extend the church but to make it more imposing. The roof of the nave was raised and the clerestory added, and crenellated parapets were added to the nave, side aisles and tower to give the whole church its present ‘visually assertive’ appearance and the east end of the south aisle a slightly rakish aspect. There were no alterations to the external structure after the early seventeenth century possibly because the Fermor family, the lords of the manor, moved to Tusmore.

By the late eighteenth century most of the rectors were non-resident and the church and its monuments were in disrepair. A major refurbishment took place at the end of the nineteenth
century under Henry Wilson (1864-1934) who had taken over the architectural practice of JD Sedding. Wilson was noted not only as an architect but also as a designer.