In mediaeval times the manor of Waterton was held from the Turbervilles, Lords of
Coity. During the 14th century the Denys family held the manor from that lordship. A charter of 1379 concerns
Johan Denys de Watirton being leased land by
Margam Abbey at
Bonvilston during the wardship of John Norreis, son and heir of John Norreis of Lachecastel.
Sir Gilbert Denys (died 1422) of
Siston, Gloucestershire was probably born in about 1350 in Glamorgan, probably the son of John Denys of Waterton. In 1415 Sir Gilbert Denys, by then well established in Gloucestershire, is recorded as renting land in Waterton from the late Lord of Coity, Sir Roger Berkerolles (died 1411), whose lordship was then held during the minority of his heir by Isabel de Beauchamp,
suo jure Lord of Glamorgan. The Denys family are recorded in ancient Glamorgan charters, the earliest mention being in 1258, when
Willelmo le Denys witnessed a charter effecting an exchange by Gilbert de Turberville, Lord of Coity, of lands in Newcastle, Glamorgan, with Margam Abbey. Clark, supported by the Denys pedigree in the "Golden Grove Book of Welsh Pedigrees" believed this
William Denys to have originated in Gloucestershire and to have married a Turberville. ==Sources==