A small priory was attached to it, where four monks "seconded" from Norwich Cathedral Priory looked after the priory's West Norfolk affairs; traces of it are seen in cottages bordering the churchyard.

The Norman church survives only in the internal arches of the west towers and at the base of the southern one outside. In the 13^th century the rest seems to have been totally rebuilt. Again only the magnificent chancel arcades survived 15th century enlargements and alterations by wealthy merchants and members of the Trinity Guild, whose hall stands opposite the church, across the Saturday Market Place: a grander clerestory and unusual round east window, and the great west window, whose glass of 1928 includes scenes from the town's history. The northwest tower had to be rebuilt in 1453, apparently subsidence into the soft ground had caused its predecessor to lean dangerously.

The nave and aisles had to be rebuilt completely after a gale in 1741 blew down a spire which formerly crowned the southwest tower. The contemporary furnishings provided for Brettingham's cautiously Gothic shell were cleared away by Victorian restorers with the exception of the superbly carved pulpit and tester.

The Victorian restoration of 1874, under the direction Sir George Gilbert Scott, cleared out galleries which had been installed over the aisles and over the crossing and "opened" the church from end to end, leaving it much as it appears now. A programme of installing stained glass in the aisle windows, instead of the plain glass of the 18^th century, brought colour back to the nave. The windows are not top quality but are a source of great interest to visitors: a leaflet to describe them in detail was found to be a necessary addition to our publications. The crowning touch was the huge reredos, designed by G F Bodley and erected in 1899.