England–Wales border after Harold's death at the Battle of Hastings, Wales was again divided without a leader to resist the Normans. Immediately after the Norman conquest of England, King William installed one of his most trusted confidants, William FitzOsbern, as Earl of Hereford. By 1071 he had started the building of Chepstow Castle, the first castle in Britain built of stone, near the mouth of the Wye. It served as a base from which the Normans continued to expand westward into south Wales, establishing a castle at Caerleon and extinguishing the Welsh kingdom of Gwent. William also installed Roger de Montgomerie at
England–Wales border of Wessex in about 885. Alfred's son Edward the Elder also secured homage from the Welsh, although sporadic border unrest continued. In the early 10th century, a document known as "The Ordinance Concerning the Dunsaete" records procedures for dealing with disputes between the English and the Welsh, and implies that areas west of the Wye in Archenfield were still culturally Welsh. It stated that the English should only cross into the Welsh side, and vice versa, in the presence of an appointed man who had the responsibility of making sure that the foreigner was safely escorted back to the crossing