Iorwerth ab Owain Gwynedd (or Iorwerth Drwyndwn) (1145–1174), meaning "the broken-nosed", was the eldest legitimate son of Owain Gwynedd

Owain Gwynedd

Owain Gwynedd ap Gruffydd , in English also known as Owen the Great, was King of Gwynedd from 1137 until his death in 1170. He is occasionally referred to as "Owain I of Gwynedd"; and as "Owain I of Wales" on account of his claim to be King of Wales. He is considered to be the most successful of...

 (the king 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...

) and his first wife Gwladys (Gladys) ferch Llywarch. He married Marared ferch Madog

Madog ap Maredudd

Madog ap Maredudd was the last Prince of the entire Kingdom of Powys, Wales and for a time held the Fitzalan Lordship of Oswestry.Madog was the son of Maredudd ap Bleddyn and grandson of Bleddyn ap Cynfyn. He followed his father on the throne of Powys in 1132...

. His son 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...

 eventually united the realm and became known as Llywelyn Fawr and is one of Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

's most famous monarchs. Iorwerth was killed in battle at Pennant Melangell, in Powys, during the wars deciding the succession following the death of his father.