Gwrgan Fawr (died c. 645) was a king of Ergyng

Ergyng

Ergyng was a Welsh kingdom of the sub-Roman and early medieval period, between the 5th and 7th centuries. It was later referred to by the English as Archenfield.-Location:...

, a south-east

South Wales

South Wales is an area of Wales bordered by England and the Bristol Channel to the east and south, and Mid Wales and West Wales to the north and west. The most densely populated region in the south-west of the United Kingdom, it is home to around 2.1 million people and includes the capital city of...

 Welsh

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...

 kingdom of the early medieval

Early Middle Ages

The Early Middle Ages was the period of European history lasting from the 5th century to approximately 1000. The Early Middle Ages followed the decline of the Western Roman Empire and preceded the High Middle Ages...

 period.

He was the son of Cynfyn

Cynfyn

King Cynfyn was the King of Ergyng, a kingdom of south-east Wales in the early medieval period. He was the son of Peibio Clafrog.-Life:...

 and rightful heir to the Ergyng throne which, however, was initially usurped by Gwrfoddw

Gwrfoddw

King Gwrfoddw was the King of Ergyng, a south-east Welsh kingdom of the early medieval period. He usurped the throne from Gwrgan ap Cynfyn.-Life:...

. Gwrgan later features as king in charters in the Book of Llandaff

Book of Llandaff

The Book of Llandaff is a 12th century compilation of documents relating to the history of the diocese of Llandaff in Wales...

 associated with Bishop

Bishop

A bishop is an ordained or consecrated member of the Christian clergy who is generally entrusted with a position of authority and oversight. Within the Catholic Church, Eastern Orthodox, Oriental Orthodox Churches, in the Assyrian Church of the East, in the Independent Catholic Churches, and in the...

s Oudoceus

Oudoceus

Saint Oudoceus or Saint Euddogwy is generally known as the third Bishop of Llandaff. In reality, he was probably a 7th century 'Bishop of Teilo' based at Llandeilo Fawr...

 and Iunapeius.

Another Gwrgan is the Gwrgan Frych ('the Freckled') who appears in the Life of Saint Cadog

Cadoc

Saint Cadoc , Abbot of Llancarfan, was one of the 6th century British Christian saints. His vita twice mentions King Arthur. The Abbey of Llancarfan, near Cowbridge in Glamorganshire, which he founded circa 518, became famous as a centre of learning...

ruling further west in Glywysing. Cadog died some years earlier, but the association may have really been with the saint's successors at Llancarfan Abbey.

When Gwrgan died, the throne of Ergyng

Ergyng

Ergyng was a Welsh kingdom of the sub-Roman and early medieval period, between the 5th and 7th centuries. It was later referred to by the English as Archenfield.-Location:...

 was inherited, not by his sons Caradog and Morgan, but by his maternal grandson, Athrwys

Athrwys ap Meurig

Athrwys was a Prince, possibly a King, from Gwent in Wales, who is generally accepted as having lived in the early 7th century.-Lineage:...

.