History of Gwynedd during the High Middle Ages

The history of Gwynedd in the High Middle Ages is a period in the History of Wales spanning the 11th through the 13th centuries. Gwynedd, located in the north of Wales, eventually became the most dominant of Welsh principalities during this period. Distinctive achievements in Gwynedd include further development of Medieval Welsh literature, particularly poets known as the Beirdd y Tywysogion (Welsh for Poets of the Princes) associated with the court of Gwynedd; the reformation of bardic schools; and the continued development of Cyfraith Hywel (The Law of Hywel, or Welsh law). All three of these further contributed to the development of a Welsh national identity in the face of Anglo-Norman encroachment of Wales.

Gwynedd's traditional territory included Anglesey (Ynys Môn) and all of north Wales between the River Dyfi in the south and River Dee (Welsh Dyfrdwy) in the northeast. The Irish Sea (Môr Iwerddon) lies to the north and west, and lands formerly part of the Powys border the south-east. Gwynedd's strength was due in part to the region's mountainous geography which made it difficult for foreign invaders to campaign in the country and impose their will effectively.

Gwynedd emerged from the Early Middle Ages having suffered from increasing Viking raids and various occupations by rival Welsh princes, causing political and social upheaval. With the historic Aberffraw family displaced, by the mid 11th century Gwynedd was united with the rest of Wales by the conquest of Gruffydd ap Llywelyn, followed by the Norman invasions between 1067 and 1100.

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