Built in the 5th and 6th century as a defensive wall from Mam Tor to Shatton Edge and once extended for half a mile across the full width of the dale north of Bradwell.
Excavations show the rampart stood 8 feet high and was 22 feet wide at its base. The ditch was of equal width and a further 6 feet deep.
Many historians believe it may simply have been a boundary, a powerful declaration of Mercian dominance. The effort involved does seem a bit over the top for that but there is a precedent in Offa's Dyke.
Another option is that it was built as a defensive battle line and some evidence for this can be conjectured. Local legend tells of an unrecorded Dark Age battle at which King Edwin of Northumbria was captured and subsequently executed. Locals remember the 'EDEN TREE' where, according to folklore, Edwin was hung. This tree stood until recently at a spot north of the village near the turn for Brough.