Syleham is 6 miles E of Diss; the church standing alongside the river Waveney which forms the Norfolk border. The land is largely arable country of low hills, but cattle graze in the pastures by the river. The church stands alone, the rest of the village standing on a low hill 0.7 miles to the SE.

St Margaret's has a nave, chancel and round W tower. At the W angles of the nave the quoins are large and irregular, suggesting an 11thc. origin. The nave is low now, but a mark on the tower shows that the roof was once more steeply pitched. The lowering may date from the 15thc., when the nave windows were renewed and the S doorway and its porch added. The 13thc. N doorway is blocked. The nave is of flint, but the eastern bays on both sides have been rebuilt using red brick and flint. On the S this bay projects slightly from the line of the nave wall, and it is possible that chapels have been removed at some time. To the same campaign belong the brick buttresses on the S side of the nave. Inside, there is a blocked N rood stair; the tower arch is small and plain, and the chancel arch is 15thc. work. The chancel was not rebuilt with the nave, and is considerably higher and out of scale with the nave. It is of flint and dates from the early 13thc., to judge from two plain lancets on the N side, but the S windows were replaced in the 14thc. and 15thc. The E window is 19thc. The flint tower is of two storeys; the upper 14thc. and decorated with chequer patterns in light and dark flints. The battlemented parapet is of brick. As is commonly the case, the lower storey is difficult to date; Mortlock and Pevsner both say Norman, Mortlock also detecting earlier masonry at the base. A stone on the S wall of the nave records that the roof leads were repaired in 1737. The present timber roof is 19thc. The font is small, plain and octagonal, possibly 14thc. according to Mortlock. It stands on a much earlier base with angle volutes; probably part of the inverted bowl of a 12thc. font. This is the only Romanesque sculpture on the site.

In his will of 942 x 951, Theodred Bishop of London bequeathed land at Syleham to his sister’s son Osgot (Sawyer S 1526). There were two holdings in Syleham in 1086. The first was held as a manor by Ulf before the Conquest, and in 1086 by Robert de Tosny. This included 2½ carucates of land, 8 acres of meadow and woodland for 150 pigs. There was also a church with 16 acres of land. The second, a holding of two carucates, was in the possession of a free man of Bishop Stigand before the Conquest, and before him it was held by bishops Aethelmar and Herfast. In 1086 this still belonged to the fief of the Bishop of Thetford. In addition to the ploughland there were five acres of meadow, woodland for 60 pigs and a mill. In 1174 the church was the site of a significant event when Roger Bigod swore submission to Henry II and surrendered his castles at Framlingham and Bungay. The dedication to St Margaret dates at least from the 13thc.; that to St Mary apparently to the 19thc. Locally the church is St Margaret's, but both the St Edmundsbury Diocesan directory and the Church of England website give the dedication as St Mary's.

Benefice of Hoxne with Denham, Syleham and Wingfield.

It seems certain that the font base is an inverted font bowl cut down, although no other font in the area follows this design.