The following is an excellent description of the Dyke,taken from The Bedside Ramblerby Christopher Somerville:
Offa’s Dyke is a symbol of division and mistrust, an ancient barrier between Welsh and English that runs the entire length of the border between the two countries. A low bank of earth and stones, five or six feet high, is all you are likely to see of the Dyke on the ground. Seen from the air the Dyke can be made out winding round bluffs,clinging to the edges of escarpments and diverging to cross rivers at suitable points – almost always with a clear view into the country lying to the west.
There was good reason for this westward aspect. The Dyke was built in about AD 790 on the orders of Offa, King of Mercia, to mark the boundary between his then relatively peaceful kingdom and his long-term Welsh adversaries. It provided not only a tangible, undeniable frontier and statement of separateness of the two countries and their cultures, but also an excellent grandstand from which Offa’s people could observe and report back to their king what the unruly neighbours were up to.
An extraordinary amount of organisation must have been needed in planning the Dyke, surveying it and gathering the labourers to build it to the original height of 12 feet or more. Twelve hundred years later it still stands along the border to perpetuate the name of King Offa and the memory of his domination of southern England.
November 9th, 2016