A small oblong Saxon building with an apse at the altar or east end has stood on this site from about the middle of the 10th century. Conclusive evidence of its being dated within the Saxon period has been presented by several researchers and writers.
The building stone is 'clench' and imported limestone. The latter material was available nearby and could have been conveyed by 'Roman' roads or river. The local stone mason and carpenter would have been employed on the job, perhaps with a more experienced overseer.
During the next three centuries the church of St. Mary was improved and enlarged as the needs of the community arose. The present south aisle was built in the twelfth century, and the thirteenth century saw the addition of a north aisle and the chancel rebuilt and squared at the east end. A typical Hertfordshire tower of three stages was added in the fourteenth century with a three-light decorated window at its west end.In the fifteenth century the porch and priest's chamber above it (parvise) was added at right angles to the south side with an opening into the south aisle. Inside the porch, on either side, are ston benches set into the walls; above them are mullioned windows once enclosed with coloured glass.
The exterior of the building took its present form in the late nineteenth century, with buttresses added to both the north east and south east corners of the aisles. The roof has a double pitch.
The opening from the south porch into the church is Norman with pilgrim marks by it. The original oak door was restored in 1882.
On entering the south aisle one is faced by a Saxon wall. This is the oldest part of the church, 950-1000 A.D. Two semi-circular arches with square piers are cut into this wall, the western-most one showing Romanesque work at the springing. High above (12 feet from the floor) on the west arch is a mutilated Saxon rood or cross, carved in chalk, of a figure of Christ 5 feet tall and robed. The head is in sharp relief in the Christus Dominus position. The features are prominent and a moustache covers the upper lip. The Alb (robe) is girded at the waist by a cord or belt with a cross on the front. The ankles are clearly visible but the feet and arms are missing. Possibly when the beams for the roof were raised and the arch lifted between the 12th and 14th centuries, mutilation took place. The veiled crucifix was not used after the 12th century, the nude figure taking its place. Only two similar Saxon figures are known to exist in the country.
In a niche in the south wall of the aisle lies an effigy in Purbeck Marble of a Knight Templar in chain mail with visor down and legs crossed,William de Lanvalei II, early thirteenth century.
Compiled by S. Esmé Overman.