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
Upper Wye Gorge fritillary and the white admiral. Upper Wye Gorge Upper Wye Gorge is a Site of Special Scientific Interest (SSSI), noted for its biological and geological characteristics, around Symonds Yat in the Upper Wye Valley on the Wales–England border. The site is listed in the 'Forest of Dean Local Plan Review' as a Key Wildlife Site (KWS). The SSSI, of which are in England and are in Wales, notified in 1969, is located north east of the town of Monmouth. It lies within the civil parishes of Goodrich and Whitchurch in Herefordshire, English Bicknor in Gloucestershire and within the community of