Owain ap Gruffudd was King of Gwynedd, North Wales, from 1137 until his death in 1170, succeeding his father Gruffudd ap Cynan. He was called Owain the Great and the first to be styled "Prince of Wales", and the "Prince of the Welsh". He is considered to be the most successful of all the North Welsh princes prior to his grandson, Llywelyn the Great. He became known as Owain Gwynedd to distinguish him from the contemporary king of Powys Wenwynwyn, Owain ap Gruffydd ap Maredudd, who became known as Owain Cyfeiliog.

Wales in the High Middle Ages covers the 11th to 13th centuries in Welsh history. Beginning shortly before the Norman invasion of the 1060s and ending with the Conquest of Wales by Edward I between 1278 and 1283, it was a period of significant political, cultural and social change for the country.