bred at the instigation of the Devil between the sons of Gruffudd ap Llywelyn, Namely Owain Goch and Dafydd on the one side, and Llywelyn on the other. And then Llywelyn and his men, trusting in God, awaited, unafraid on Bryn Derwin the fierce coming of his brothers, and a mighty host along with them. And before the end of one hour Owain Goch was captured and Dafydd fled, after many of his host had been slain. Imprisonment and release With his brothers out of the way, Llywelyn proceeded to extend Gwynedd's territory until it encompassed much of the rest of Wales, in the process claiming the title of Prince of Wales. Owain was imprisoned again, and remained in prison until 1277. In a contemporary poem of the 13th century, court poet Hywel Foel ap Griffri laments Owain's captivity, describing him in the opening line as: Gŵr ysydd yn nhŵr yn hir westai (a man who is in the tower, long a guest). It is unclear where Owain was imprisoned, but some scholars believe he was kept in Dolbadarn Castle near Llanberis. Wherever he was kept, Llywelyn reluctantly released Owain in 1277 under the terms of the Treaty of Aberconwy, after some 20 years of captivity. Upon being released, Owain retired to his estate in north-west Wales and never again mounted a serious challenge to his brother Llywelyn's rule. He is thought to have died c. 1282. See also List of rulers of Wales References J. Beverley Smith (1986) Llywelyn ap Gruffudd: Tywysog Cymru (Gwasg Prifysgol Cymru, Cardiff) [In Welsh] 1282 deaths Monarchs of Gwynedd 13th-century Welsh monarchs Year of birth unknown