The medieval earthwork popularly known as the Battle Ditches is the surviving south-west corner of a large, rectangular circuit enclosing the medieval town area. The course of the ditch, now mostly buried, has been traced round much of the town through archaeological excavations over the years. It has also acquired many names in its history; in some medieval documents it was the Magnum Fossatum, Latin for Great Ditch, and later it became known as the Repell Ditches or Battle Ditches. It is perhaps best referred to as the Town Ditch, as it was essentially a Norman and medieval boundary marker. Presumably it defined the area of the town within which market tolls could be levied and other administrative functions exercised, as well as having some sort of general defensive purpose.
The origins and story of the Town Ditch is bound up with the Norman Earls of Essex and Walden Castle, which was probably built by Geoffrey II de Mandeville, Earl of Essex in around 1140.
The so-called ‘Outer Bailey’ ditch encircling the hill occupied by the Castle and St Mary’s Church, is essentially the first Norman town enclosure ditch, probably contemporary with the Castle. It may reflect Earl Geoffrey’s attempts to maximise the economic value of his manor of Walden by defining his new ‘market’ on the hill-top (in 1141 he persuaded the Empress Maud to transfer the market rights from Newport to his new seat at Walden). The south east corner of this Norman ‘town ditch’ was identified on the Common in 2013, first by geophysics (Dr Tim Dennis and Ralph Potter) and then confirmed in excavation by Professor Carenza Lewis and Access Cambridge Archaeology. Pottery dating from the mid-twelfth century was found in the bottom of this ditch, but the ditch does not appear to have been in use for very long and was deliberately back-filled, probably later in the twelfth century.
In the early twelfth century the de Bohuns inherited the manor of Chipping [Market] Walden and ushered in a new phase of town developments. The greater Town Ditch circuit, of which the Battle Ditches form the south-west corner, belong to this period. Within the Town Ditch, a rectilinear street plan was laid out on a grid and an extensive new market place was added on the south-facing slope below the Church and Castle.
This new Town Ditch shared the same northern ditch as the earlier, Norman town ditch. The line of this ditch was confirmed in excavation in 2005 by Essex County Council Field Archaeology Unit on the north side of Castle Street. The Battle Ditches /Town Ditch have been excavated at a number of points since the 1950s, so the route round most of the town is well established, however it is uncertain exactly what course it took round the north-west corner, where it has been suggested that the low-lying and marshy terrain of Swan Meadows could have formed a natural geographical barrier. However, recent archaeological work off Freshwell Street (2017) has apparently picked up the line of the Town Ditch in that area.
Evidence from various sections excavated across the Town Ditch suggests that the Ditch later fell out of use and started to fill up with soil and rubbish. By the end of the 14th century, substantial lengths of the Town Ditch had been deliberately back-filled and levelled; perhaps it had become a hindrance to accessing fields and property on the town’s outskirts. Yet the line of the Ditch remained preserved in property boundaries, in some places right up to the present day, as on the north side of Castle Street. Maybe the south-west corner of the Town Ditch (the Battle Ditches which survive today) survived because this area was more remote from the town centre and not densely developed until much later times.