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
River Wye, Derbyshire just south of Tideswell, then through Ashford in the Water and Bakewell, and south of Haddon Hall, before meeting the River Derwent at Rowsley. The main tributary of the river is the River Lathkill, which enters approximately one mile from its mouth. The River Wye is one of Derbyshire's best known rivers and is popular with anglers owing to the large numbers of wild brown, rainbow trout and grayling it contains. The alkalinity of the Wye provides a rich source of nutrients that leads to an abundance of insects, invertebrates and other wildlife. This ensures that the Trout and Grayling