England–Wales border point. In 926, Edward's successor Athelstan, "King of the English", summoned the Welsh kings including Hywel Dda of Deheubarth to a meeting at Hereford, and according to William of Malmesbury laid down the boundary between England and Wales, particularly the disputed southern stretch where he specified that the eastern bank of the Wye should form the boundary. By the mid-eleventh century, most of Wales had become united under the king of Gwynedd, Gruffudd ap Llywelyn. In 1055, he marched on Hereford and sacked the city. He also seized Morgannwg and the Kingdom of Gwent, together with substantial territories east of
Wye Valley in the area of Symonds Yat and Slaughter Stream Cave near Berry Hill. At St Arvans, near Chepstow, the underground watercourses have carved out long cave systems, which exit at Otter Hole at the base of Piercefield cliffsthe only cave system in England or Wales which can only be reached through a tidal sump, making it a mecca for experienced cavers. Lancaut and Ban-y-Gor are Gloucestershire Wildlife Trust nature reserves. They both have SSSI status being part of the nationally important Lower Wye Gorge SSSI and within the Wye Valley AONB. The Wye Valley is important for its rich wildlife