Debenham is a small town skirted by the river Deben (little more than a stream at this point), in central Suffolk some 8 miles E of Stowmarket. It is built on a hill, small but steep-sided, with the church at the summit and the High Street running past it from N to S. The church provides a perfect example of the development of English medieval architecture. Its sturdy W tower is 11thc.; its chancel is 13thc. Early English; the nave is 15thc. Perpendicular and the W Galilee is 14thc. Decorated. In more detail, the lower parts of the flint tower probably date from the first half of the 11thc., before the Conquest, and show long and short work at the angles (best seen at the NW) and coursed and herringbone masonry. On the S wall are two simple round-headed lancets, but they are not identical. The lower is thinner with long and short masonry jambs and belongs with the first phase described above. The upper is broader with a slight chamfer around the opening, pointing to a post-Conquest date. The tower arch inside belongs to this second campaign. The tower received its belfry stage, including the bell-openings, around 1380, the date of a bequest of 20 marks from Walter Hart. The ashlar embattled parapet is a later addition. It apparently had a small spire that was struck by lightning in the 17thc. and taken down in 1667. There is no obvious trace of the Romanesque nave and chancel that belonged to the tower. The next phase of the present building is the 13thc. chancel that replaced its Romanesque predecessor. The N windows are plain pointed lancets but those on the S, facing the town, are two-light plate tracery windows, indicating a date towards the middle of the 13thc. The E window is renewed, but is a simple triplet as might be expected. Inside, the piscina is also 13thc. On the S side stands the impressive tomb of Sir Charles Framlingham (d.1595) and his wife. The next campaign involved the building of the Galilee, a two-storey W porch of flint with a knapped flint façade and battlements on the lateral walls. It dates from the late 14thc. The Norman nave was completely remodelled in the first half of the 15thc., when aisles were added with tall, four-bay arcades. The chancel arch was replaced at the same time as the arcades were built. Mortlock points out that the 13thc. jambs of the arch were raised by inserting new sections, and new capitals were carved, like those of the nave arcades. The arch became unstable, and by 1875 it was propped up by a timber support, and the chancel was blocked off as unsafe (Watling). It was restored in 1883. The nave aisles are tall too, and lit by three-light windows with segmental two-centred heads. The walls of the central vessel were raised to provide clerestories with two triple-light windows per bay. The Perpendicular work was faced externally with knapped flint, and embattled parapets were provided for nave and aisle walls. The N and S doorways are positioned below half-height windows in the aisles, and have no porches. The original nave buttresses have flushwork panels, but two have been replaced in the centre of the S wall, along with the section of aisle wall between them. This work is done in red brick, and probably dates from 1567-68 when money was bequeathed to repair the broken and decayed windows. The S aisle windows lost their tracery and mullions during the 18thc, and were patched with brick and timber, and in the same period the SE corner of the church was consolidated with huge brick buttresses. These disfigurements were reversed in the restorations of 1882-87 by H. J.Green of Norwich, who also restored the chancel. The tracery of the new S aisle windows was copied from those in the N aisle. Only the tower arch is recorded here.
The Domesday Survey lists two manors in Debenham; one held by Godwig, a free man commended to Saxi before the Conquest, the other by Saxi himself. Godwig's manor consisted of 40 acres with an acre of meadow, a quarter of the church of St Mary and three-quarters of the church of St Andrew. Saxi's included another quarter of St Mary's church one carucate and 22 acres of ploughland, four acres of meadow and woodland for 100 pigs. In 1086, Godwig's manor belonged to the Bishop of Bayeux, and Saxi's to Ralph de Savenay who held it from Ranulph Peverel. The remaining half of St Mary's and the fourth quarter of St Andrew's were held by Robert Malet in 1086. Smaller holdings were 10 acres held by Wulfgeat, a free man commended to Eadric before the Conquest and by William Goulafre from Robert Malet in 1086; two acres held by a man commended to Eadric before the Conquest and by Robert Malet in 1086, and half an acre held by 1 free man, Aethelric, commended to Saxi before the Conquest and by the Bishop of Bayeux in 1086. A Monday market was granted by Henry III in 1221, and a Friday market and a fair in 1222, all to Robert Aguillon (Aguillun).
Debenham and Helmingham benefice, i.e. Aspall, Debenham and Kenton and Framsden, Helmingham, Pettaugh and Winston.