One of the earliest Christian sites in Britain - has been a centre of Christianity since A.D. 634, when St Birinus began a mission to Wessex. The imposing church is all that remains of an Augustinian abbey, founded in 1140. It was enlarged in the 13th and 14th centuries and restored in the I9th. It has good medieval stained glass, a remarkable Jesse window, and a rare lead font.
The church of Dorchester Abbey, as it stands today, was built entirely by the Augustinian Canons, although there are traces on the north side of Saxon masonry, probably part of the ancient cathedral. The whole length of the church is 230 feet (70 m), its width 70 feet (21 m) and its height 55 feet (17 m). The north transept and its doorway are Norman.
The north side of the nave and chancel arch are Early English Gothic. The choir, south side of nave, south aisle are Decorated Gothic. The south porch is late Perpendicular Gothic. The very rich sanctuary, with its highly decorated windows (including the famous east window one known as the Jesse Tree window) and ornately carved sedilia and piscina, dates from 1330.
Other fittings include one of the few surviving lead fonts in England, frescoes of 1340 and several monuments, especially the well-known "swaggering knight" effigy formerly believed to be Sir John Holcombe who died in 1270 but it is more likely that it is William de Valence the Younger (died 1282 at the Battle of Llandeilo Fawr), son of William de Valence, 1st Earl of Pembroke.