Cadwallon ap Gruffydd

 Cadwallon ap Gruffydd (c. 1097 – 1132) () was the eldest son of Gruffudd ap Cynan, king of Gwynedd.
Early life.
Cadwallon was born in the village of Walesey in the county of Caernarvonshire in Wales. His mother was Angharad ferch Owain, the daughter of Owain ab Edwin.
Cadwallon's siblings were Hywel ap Gruffydd, Rhanullt verch Gruffydd, Tudwal ap Gruffydd, Gwenllian verch Gruffydd, Elen verch Gruffydd, Merinedd verch Gruffydd, Susanna verch Gruffydd, Cadwaladr ap Gruffydd, Gwenllian II ap Rhys (born verch Gruffydd), Owain Gwynedd, Idwal ap Gruffydd, Duling ap Gruffydd, Membyr "Ddu" ap Gruffydd, Rhael verch Gruffudd, Annes verch Gruffydd, Margred ap Gruffydd, and Gwladys Rhanullt verch Gruffydd. Cadwallon sisters Gwenllian married Gruffydd ap Rhys and Susanna married Madog ap Maredudd. Cadwallon was half brother of Margred verch Gruffydd; and Gwenllian ferch Gruffydd.
Mid life.
Cadwallon appears first in history records as conspiring with his older brother Owain Gwynedd to take the district of Meirionydd within the medieval kingdom of Powys in 1123. In 1125 he killed the three rulers of the district Dyffryn Clwyd, being Meilyr ab Owain, Rhiryd ab Owain, and Gronw ab Owainhis maternal uncles, "i.e.", his mother's brothers. The district cantref of Dyffryn Clwyd was then annexed into the kingdom of Gwynedd. Cadwallon is notoriously remembered by historians for murdering his uncles, as this ended the reign of the house of Edwin of Tegeingl as a regime.
Cadwallon then is found a few years later in the valley of Dee at Mold, Flintshire, Wales. With his older brother Owain Gwynedd (c.1100–70) they worked together to restore the power of Gwynedd for their ageing father. They were military leaders and directed their father's armies which added the land regions of Meirionydd, Rhos, Rhufoniog, and Dyffryn Clwyd to the kingdom of Gwynedd.
Later life and death.
In 1132 Cadwallon forged eastward to conquer more land for the kingdom of Gwynedd but was stopped in the area of Nanheudwy in 1133, near the town of Llangollen. An army from the kingdom of Powys then defeated and killed him. His uncle Einion ab Owain ab Edwin was one of the instigators, to avenge his brothers' deaths. Cadwallon's cousin Cadwgan ap Grown ab Owain also played a part in his slaying. Other cousins were also involved in Cadwallon's murder.
Family.
Cadwallon married Gwenllian from an unknown family line. They had a son named Cunedda ap Cadwallon ap Gruffydd ap Cynan. Genealogy records indicate he also had another wife by the name of Alice of an unknown family line and had two sons.
He is not to be confused with the other four "Cadwallon"s (and nearly a dozen closely related named personageshomonyms, homographs and homophones) who are historically significant in Welsh history.