Perfeddwlad or Y Berfeddwlad was an historic name for the territories in Wales lying between the River Conwy and the River Dee. comprising the cantrefi of Rhos, Rhufoniog, Dyffryn Clwyd and Tegeingl. Perfeddwlad thus was also known as the Four Cantrefs. Early history For much of its history the area had been known as Tegeingl, after the Celtic tribe Deceangli which inhabited North East Wales since the Iron Age. This was also the name of the most easterly cantref of the region. As the Kingdom of Gwynedd emerged as the dominant power in North Wales, the area also became known as Gwynedd Is Conwy (Gwynedd "below" the Conwy River). The name Y Berfeddwlad appears in the High Middle Ages, as the rivalries between Gwynedd, Powys, and the Anglo-Saxon England (and later Normans) intensified. The name is a contraction of "Perfedd" and "gwlad" meaning heart-land or middle-country as the area became a centre of conflict. Later history Shortly after the death of Owain, the ruling Prince of Gwynedd, his son and heir Hywel was ousted in a coup led by his stepmother; he was replaced by his step-brothers Rhodri, Maelgwn, and Dafydd, who ruled jointly. However, within a year, the ruling brothers fell into dispute, forcing Maelgwn to flee to Ireland, while Dafydd and Rhodri eventually divided Gwynedd between them; Angelsey and the Perfeddwlad went to Dafydd. In 1194, Llywelyn Fawr, the senior heir of Owain Gwynedd (being the eldest son of Iorwerth Drwyndwn, the next eldest son of Owain Gwynedd after Hywel), defeated Dafydd in the Battle of Aberconwy, and took over the Perfeddwlad. Following Rhodri's death the following year, Gruffudd, another grandson of Owain Gwynedd by yet another son, took over the remainder of Gwynedd; when Gruffudd died in 1200, Llywelyn inherited these lands as well. Llywelyn's expansionist conflicts with Reginald de Braose, William Marshal, and Powys Wenwynwyn, lead to his dominance of Wales, but following his death, his brother-in-law, King Henry III of England, temporarily invaded the Perfeddwlad in order to force Llywelyn's son - Dafydd - to agree (by the Treaty of Gwerneigron) to limit his authority to Gwynedd. Henry took Dafydd's bastard elder brother Gruffydd hostage to ensure compliance (Gruffydd's potential release represented a threat to Dafydd, as Welsh Law allowed acknowledged bastards to inherit). Following Gruffydd's accidental death a few years later (while trying to escape), Dafydd forged an anti-English alliance against his uncle (King