The prehistoric and Roman periods are represented by a scatter of stray finds from around the town, but there is little evidence for any density of settlement in the immediate area before the late Saxon/early medieval period.
The Domesday Book demonstrates that there was a village at Rayleigh at the end of the Saxon period. Swein of Essex built his castle there at some point between 1066 and 1086, making it one of the earliest Norman castles in the country (Rumble, 1983). There is still a substantial motte and bailey on the site and the outer bailey was still visible within this century. It has been suggested that there was a hundredal market at Rayleigh market (Eddy and Petchey, 1983), and there are also references to a market and fair dating to 1227. Unlike other Essex towns attached to castles there is no evidence that there was ever a town enclosure, although it is possible that the outer bailey served a defensive function for the townsfolk.
There are two possible interpretations for the town morphology; either the market-place was a cigar-shaped widening of the High Street or that it was sited in the area between Bellingham Lane, London Hill and Church Street, forming an infilled elongated triangular market-place. The location of the church, which contains 12th-century elements, is on the eastern edge of the town, possibly marking the location of the original settlement.
The castle was abandoned in the 14th century, and the land used first as part of the royal stud, and then in the 17th century as a farmyard. The town appears to have remained as a small market town with a small but stable population until the beginning of the 20th century when the introduction of the railway led to its growth as a commuter town for London.