This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2009)

House of Dinefwr
Coat of arms of Deheubarth
Country	Wales
Parent house	House of Manaw
Titles	King of the Britons, King of Dyfed, King of Deheubarth, King of Powys, Prince of Seisyllwg, Prince of Gwynedd, Prince of Deheubarth
Founder	Cadell ap Rhodri, Prince of Seisyllwg
Founding year	854
Ethnicity	Welsh
Cadet branches	House of Mathrafal House of Tudor

The House of Dinefwr was a royal house of Wales and refers to the descendants of Cadell ap Rhodri King of Seisyllwg, son of Rhodri the Great. The prominent House of Tudor is directly related in the male-line from the House of Dinefwr.

With the death of Rhodri Mawr, the kingdom of Gwynedd passed to his eldest son Anarawd ap Rhodri. Rhodri's second son Cadell ap Rhodri, however, looked outside Gwynedd's traditional borders and took possession of the Dark Ages kingdom of Dyfed by the late 9th century, establishing his capital at the citadel of Dinefwr. Cadell ap Rhodri's descendants are designated Dinefwr after the citadel from which they would rule Dyfed. The Dinefwr dynasty under king Hywel Dda would unite Dyfed and Seisyllwg into the kingdom of Deheubarth in the early 10th century. The Dinefwr dynasty would rule in Deheubarth until their conquest by the Anglo-Normans in the 13th century. This branch would compete with House Aberffraw for supremacy and influence in Wales throughout the 10th, 11th, and 12th century, with Powys variously ruled between them. Eventually, a cadet branch of Dinefwr would establish itself in Powys by the mid 11th century, designated Mathrafal after the castle there.

v • d • e Royal Houses of Wales House of Dinefwr · House of Aberffraw · House of Gwynedd · House of Mathrafal · House of Cunedda