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Iestyn ap Gwrgant

1045 – 1093

Last independent ruler of Glamorgan

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About Iestyn ap Gwrgant

Lived 1045 – 1093 (aged 47–48). Iestyn ap Gwrgant was a sovereign.

Iestyn ap Gwrgant (, ; 1014–1093), or Jestyn ap Gwrgant, was the last ruler of the Welsh kingdom of Morgannwg, which encompassed the counties of Glamorgan and Monmouthshire.

Lineage Iestyn ap Gwrgant was the last ruler of the royal house of Morgannwg, which had a lineage stretching back over five centuries to Tewdrig (c. 500–520). The members of this royal house had links to the other royal houses of Wales through marriage, and were descendants of the celebrated Rhodri Mawr. Iestyn ap Gwrgant's base is believed to have been at Dinas Powys, south west of Cardiff.

Norman invasion Iestyn probably ruled Morgannwg for a little less than a decade (c. 1081–1090) and is believed to have built castles in the regions of Cardiff and Kenfig. The popular version of historical events is that Iestyn, following a dispute with his rival Einion ap Collwyn, invited Robert Fitzhamon and his twelve knights into the region to settle the matter. Once invited in, they refused to leave. He was deposed c. 1090 by Norman ruler Robert Fitzhamon, lord of Gloucester, who established a lordship based in Cardiff and subsequently conquered the lowlands of Glamorgan (the Vale of Glamorgan), which was parcelled out to his followers. The mountainous parts of Glamorgan were left in Welsh control. Caradog ap Iestyn, the eldest son of Iestyn ap Gwrgant, was the only Welsh lord to retain lands in the Glamorgan lowlands after Fitzhamon had conquered them. He retained the land between the River Neath and the River Afan, and he and his descendants were known as the "lords of Afan." His descendants are thought to include the Williams family of Aberpergwm and the Powell Wilkins family of Carreg Cennen, Carmarthenshire.

Modern interpretation Flag of CardiffIestyn ap Gwrgant's arms can be seen today in a modern context as a banner of the arms forms the Flag of Glamorgan which itself forms a charge on the flag of Cardiff. Additionally the arms are found within the crest of Pontypridd Rugby Football Club, a Rugby Union team from Pontypridd within the ancient boundaries of Morgannwg. Richard Williams Morgan claimed that a reference to a son of Caratacus called Saint Cyllin was found in the family records of Iestyn ab Gwrgant and used this as evidence of early entry of Christianity to Britain "Cyllin ab Caradog, a wise and just king. In his days many of the Cymry embraced the faith in Christ through the teaching of the saints of Cor-Eurgain, and many godly men from the countries of Greece and Rome were in Cambria. He first of the Cymry gave infants names; for before, names were not given except to adults, and then from something characteristic in their bodies, minds, or manners."

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Important facts

Born
1045, Kingdom of Glywysing
Birth century
Died
1093, Rhiwbina
Occupation
Also known as
Iestyn ab Gwrgant, King of Morgannwg, Iestyn ap Gwrgant, King of Glamorgan, Iestyn ap Gwrgan ab Ithel ab Idwallon of Iestyntown

Family & relationships

Child
Caradog ap Iestyn

People in Iestyn ap Gwrgant's life

Named in this biography and alive at the same time

Contemporaries

People whose lives overlapped Iestyn ap Gwrgant's

Frequently asked questions

Who was Iestyn ap Gwrgant?

last independent ruler of Glamorgan

When was Iestyn ap Gwrgant born?

Iestyn ap Gwrgant was born in 1045 in Kingdom of Glywysing.

When did Iestyn ap Gwrgant die?

Iestyn ap Gwrgant died in 1093 in Rhiwbina.

What was Iestyn ap Gwrgant's occupation?

Iestyn ap Gwrgant was a sovereign.

Sources & further reading

· Wikipedia: Iestyn ap Gwrgant

· Wikidata: Q1087998

· DBpedia: Iestyn ap Gwrgant

Cite this page

APA: Biography.guide. (2026). Iestyn ap Gwrgant. https://biography.guide/iestyn-ap-gwrgant/

MLA: "Iestyn ap Gwrgant." Biography.guide, https://biography.guide/iestyn-ap-gwrgant/.

Chicago: "Iestyn ap Gwrgant." Biography.guide. https://biography.guide/iestyn-ap-gwrgant/.

Data last updated: 2026-09-20 · Spot an error? Report a correction.

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