Offa's Dyke

Offa's Dyke is an earth rampart built by King Offa of Mercia between 784 and 796 to provide protection for the Anglo-Saxons against Welsh attacks. It extends from the Severn estuary to the Dee, a total distance of some 170mi/272km.

After defeating Caradoc, a Welsh prince, between Abergele and Rhuddlan (south of Rhyl) Offa built the wall to mark the border between Mercia and Wales. His palace was at Sutton Walls.

The earth rampart was reinforced by a ditch on the Welsh side. It can be followed, with many interruptions, for a distance of more than 140mi/224km between the estuary of the Dee and the Wye. A second earthwork known as Wat's (or Watt's) Dyke, which is probably of somewhat later origin, runs parallel to Offa's Dyke, 3mi/5km away, for a distance of some 40mi/64km from the Dee to the Severn.