Llywelyn Fawr or Llywelyn ap Maredudd ap Cynan ab Owain Gwynedd was a second-cousin of Gruffudd ap Llywelyn and Dafydd ap Llywelyn

Dafydd ap Llywelyn

Dafydd ap Llywelyn was Prince of Gwynedd from 1240 to 1246. He was for a time recognised as Prince of Wales.- Descent :...

 of the royal house of Gwynedd

Kingdom of Gwynedd

Gwynedd was one petty kingdom of several Welsh successor states which emerged in 5th-century post-Roman Britain in the Early Middle Ages, and later evolved into a principality during the High Middle Ages. It was based on the former Brythonic tribal lands of the Ordovices, Gangani, and the...

 in the 13th Century. His father was Prince Maredudd

Maredudd ap Cynan ab Owain Gwynedd

Maredudd ap Cynan was the grandson of Owain Gwynedd, a king of Gwynedd and ruler of most of Wales in the 12th century.Maredudd is known to have fought alongside his brother Gruffudd against his uncle Hywel in 1170 and later fought on the side of his cousin Llywelyn ab Iorwerth between 1194–1197 in...

 who fought alongside his brother in an alliance with Llywelyn the Great

Llywelyn the Great

Llywelyn the Great , full name Llywelyn ab Iorwerth, was a Prince of Gwynedd in north Wales and eventually de facto ruler over most of Wales...

 to depose their uncle Dafydd

Dafydd ab Owain Gwynedd

Dafydd ab Owain Gwynedd was Prince of Gwynedd from 1170 to 1195. For a time he ruled jointly with his brothers Maelgwn ab Owain Gwynedd and Rhodri ab Owain Gwynedd....

 in 1195.

Llywelyn the Elder had a younger brother also called Llywelyn who is sometimes referred to as Llywelyn Fychan or Llywelyn "The Younger". Very little is known about Llywelyn the Elder except that he had a son called Maredudd ap Llywelyn ap Maredudd ap Cynan

Maredudd ap Llywelyn ap Maredudd ap Cynan

Maredudd ap Llywelyn ap Maredudd ap Cynan was the only known son of Llywelyn the Elder and was a great-great-grandson of Owain Gwynedd, an important prince of north Wales in the 12th Century...

.