The earthwork was constructed some time between the end of Roman rule in Britain in the early 5th century and the Norman conquest in 1066. Its original purpose is unclear, but it may have been used as a defensive fortification or as an administrative boundary. It possibly marked a 7th-century boundary for the expansionist Anglo-Saxons, or it may have been a late 8th or early 9th century boundary marker between the kingdoms of Mercia and Northumbria. In the early medieval period, the Anglo-Saxon kingdoms of Northumbria, Mercia, and Wessex struggled for control over North West England, along with the Britons and the Danes. Whatever its earlier use, the ditch has been used as a boundary since at least the Middle Ages.