The much larger size of St Mary’s Church compared to its neighbours can be explained by an entry in the Domesday Survey of 1086 which states that there was a Benedictine Priory in Aldeby. The church functioned as both the priory church and the parish church but the Priory did not survive the Reformation. Cruciform in shape, the church has retained its Norman west door with elaborately carved capitals and a zigzag arch. In 1300 the tower and north transept were rebuilt and new windows created. The 15th and 19th centuries saw further restorations. Tall chancel arches create a lofty atmosphere. The 15th century font has a late 17th century cover. The striking east window depicts the Transfiguration, with Moses on the left and Elijah on the right.