As already noted, before the Reformation, Thorpe Church was a Chapel of the Abbots of Chertsey. The local tradition regards it as having been the retreat-house for the abbot. Documents from the medieval period describe it as a "chapel" distinction from a parish church. However its undoubted use as a "chapel-of-ease" for the people of Thorpe led to its adoption as a parish church after the Reformation. Stained glass and tilework bear testimony to the link with Chertsey Abbey, and the configuration of the columns in the Nave mark this out as a house of the Benedictine Order of monks.

The column at the west end of the north aisle is a different shape to the rest, apparently to be the place of monastic discipline at which offending members of the community were purged of their sins and misdemeanours through corporal punishment.

The arcades above the nave columns date from the 13^th century, using pointed gothic arches which afford greater load-bearing capabilities and stability than their rounded Norman predecessors. The columns themselves, however, are the original, large, rounded columns which would have supported the earlier arcades. In places you can see the stone re-used from earlier, presumably failed, structures, including the royal motives of both William the Conqueror (1066 - 1087) and his son William Rufus (1087 - 1100).

The large Norman Chancel arch in the centre of the Church is built of stone from the Norman quarries at Bec. Shipped over at vast expense, this was the Saxon Abbot’s way of paying homage to the new conquering Norman king, and protecting his chapel from destruction by the invading army. The wall itself is much older, and is the original outside wall of the Abbot’s chapel. A consecration cross still survives etched into the North pillar. The Nave contained twelve Norman columns of which only eight are still extant. 

A Tudor Tower

The last major work in the period before the Reformation is the tower at the west end of the church. This has a pleasantly arched doorway in the Perpendicular style. Like many churches St. Mary's would be the subject of repairs and alterations throughout its history. It is probable that four Norman arches which formed the west end of the Nave became derelict or unsafe. In their place was built a tower in the reign of Henry VII (1485 - 1509). Curiously although using the new material of brick, the tower is constructed in a style more appropriate to stonework. This tower is a very early example of brickwork being used to construct a tower. There was a wooden spire atop the tower for a time which no lomnger survives.