Devil's Dyke is over long and is the largest of a series of ancient Cambridgeshire dykes. In some places the bank measures high and across. Its highest point is at Gallows Hill where it measures from the bottom of the ditch to the top of the earth wall. Since the 19th century a railway line and roads have been cut through the dyke, including the combined A14 and A11 roads, and a branch line of the Ipswich to Ely rail line. From Reach, the dyke crosses farmland, before running along the edge of the July Course at Newmarket Racecourse and then through the woods of a private estate near the village of Woodditton. The Rowley Mile course is unusual in that it can have races which start in one county, Cambridgeshire, and finish in another, Suffolk. It crosses the Devil's Dyke where it has been previously levelled.
History
Devil's Dyke is the largest of several earthworks in south Cambridgeshire that were either boundary markers or designed to control movement along the trackways of Ashwell Street and the Icknield Way. When it was created, it completely blocked a narrow land corridor between the southern edge of a region of water-logged marsh in the north-west and dense woodlands in the south, so making circumvention difficult and forming an effective defensive barrier for the lands to the east. The dyke may have served as a way of controlling trade and movement in and out of the area. Findings such as the small quantity of silt in the ditch fills suggest that the dyke fell into disuse soon after it was built. The other Cambridgeshire dykes include Fleam Dyke, Brent Ditch and Bran Ditch. Black Ditches, Cavenham is a fifth earthwork guarding the Icknield Way which is in Suffolk, to the north west of Bury St Edmunds.
The name
The name Devil's Ditch or Dyke is a post-medieval one. In medieval times it was simply called the dic meaing the ditch or le Micheldyche or magnum fossatum which both mean great ditch.
Early commentators
The earthwork has been described by various different commentators since Anglo-Saxon times. The Anglo-Saxon Chronicle may refer to the Devil's Dyke in its annal for 905, when Edward the Elder is recorded as fighting and defeating the Danes of East Anglia, after first laying waste to the countryside: 'and he laid waste their land between the Dyke and the Ouse as far northward as the Fens'—' and oferhergade call hera land betwuh dicun and Wusan. call oþ da fennas norð'. Abbo of Fleury, writing in the late 10th century, described East Anglia as "fortified in the front with a bank or rampier like unto a huge wall, and with a trench or ditch below in the ground". The mediaeval Flores Historiarum, referred to "...duo fossata sancti Eadmundi..." – the two fortifications of St Edmund – when describing the battle between Edward and his adversaries.
Modern scholarship
There have been a number of excavations and investigations of the dyke in modern times, including excavations in 1923 and 1991. In 1991, little was found when a small part of the dyke was excavated prior to the construction of a new aqueduct. The results of a 1988 resistivity survey of the point where Street Way cuts through the dyke were inconclusive. The Dyke is thought most likely to be Anglo-Saxon as there would have been no strategic reason to build it in the Roman period, and the most likely context is the period of warfare between Mercia and East Anglia in the sixth and seventh centuries, when the East Anglians might have thrown it up as a line of defence.
