Gwenddoleu ap Ceidio

This is in what is now south-west Scotland and north-west England in the area around Hadrian's Wall and Carlisle during the sub-Roman period in Britain.

Carwinley, near Longtown, north of Carlisle, possibly derives from Cumbric Caer Wenddolau or Gwenddolau's Fort.

Ceidio's brother, Eliffer Gosgorddfawr was presumed to have been a king of Ebrauc, believed to be the old Roman stronghold of Eburacum.

In Welsh mythology, he is the owner of one of the Thirteen Treasures of the Island of Britain: a magical chessboard / gwyddbwyll board.

In Geoffrey of Monmouth's Vita Merlini, Myrddin (Merlinus) is said to have been driven mad with grief following the death of Gwenddoleu and to have fled into the Caledonian forest.