Owain ap Gruffudd (also known as Owain Goch [Owain the Red]) (died 1282) was brother to Llywelyn ap Gruffudd and Dafydd ap Gruffudd and, for a brief period in the late 1240s and early 1250s, ruler of part of the Kingdom of Gwynedd (in modern-day north Wales). Lineage Owain was the eldest son of Gruffudd ap Llywelyn and the grandson of Llywelyn the Great. He was imprisoned together with his father in Criccieth Castle in 1239 by his uncle Dafydd ap Llywelyn, and accompanied his father to England two years later when Dafydd was forced to hand Gruffudd over to King Henry III of England. In 1244 Gruffudd was killed when a makeshift rope broke as he attempted to escape from the Tower of London. This freed Dafydd ap Llywelyn's hand as King Henry could no longer use Gruffudd against him, and war broke out between him and King Henry in the spring of 1244. Owain meanwhile had been freed by Henry after his father's death in the hope that he would start a civil war in Gwynedd, but he remained at Chester, so that when Dafydd died unexpectedly in February 1246 without leaving an heir, his brother Llywelyn, who had supported his uncle against the king, had the advantage of being on the spot. Treaty of Woodstock Owain and Llywelyn came to terms with King Henry, but were restricted by the terms of the Treaty of Woodstock in 1247 to Gwynedd Uwch Conwy, the part of Gwynedd west of the River Conwy, which was divided between them. Gwynedd Is Conwy, east of the river, was taken over by the king, who gave it to his son, Edward. Though initially paying homage to the English, Owain and Llywelyn soon broke with Henry III in protest over the ruthless raids being conducted on the Welsh borders. The Battle of Bryn Derwin The third brother, Dafydd ap Gruffudd, came of age soon afterwards, and King Henry accepted his homage and announced his intention of giving him a part of the already much reduced Gwynedd. Llywelyn refused to accept this, and Owain and Dafydd formed an alliance against him. This led to the Battle of Bryn Derwin in June 1255. Llywelyn defeated Owain and Dafydd and captured them, thereby becoming sole ruler of Gwynedd Uwch Conwy. The medieval Welsh chronicle Brut y Tywysogion described the struggle thus: In those days great strife was