The Battle of Crug Mawr took place in September or October 1136, as part of a struggle for control of Ceredigion which had been captured by the Normans. A Welsh revolt against Norman rule had begun in south Wales, where on 1 January 1136 the Welsh won a victory over the local Norman forces at the Battle of Llwchwr between Loughor and Swansea, killing about 500 of their opponents. Richard Fitz Gilbert de Clare, the Norman lord of Ceredigion, had been away from his lordship in the early part of the year. Returning to the borders of Wales in April, he ignored warnings of the danger and pressed on towards Ceredigion with a small force. He had not gone far when he was ambushed and killed by the men of Iorwerth ab Owain, grandson of Caradog ap Gruffydd (the penultimate prince of Gwent).