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Tewdwr Mawr

520 – 584

Breton and Cornish king

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About Tewdwr Mawr

Lived 520 – 584 (aged 63–64).

Tewdwr Mawr (Breton for "Theodore the Great"; or ; ; ; ; mid-6th century) was an early medieval king in Armorica (now Cornouaille, France) and Cornwall.

Life Tewdwr was a member of the royal family of Cornouaille in Armorica. His father was Hoel, who figured in Welsh mythology about the Matter of Britain and Tristan and Iseult. Other sources give different fathers, Cadell Mawr of Seisyllwg and Cadell ap Edwin of Gwynedd. While Tewdwr was still young, his grandfather Budic II was overthrown and forced into exile at the court of Aergol Lawhir of Dyfed. Budic successfully restored himself in the 540s but Hoel seems to have predeceased him. The king attempted to protect his succession by negotiating with a neighbouring ruler, Macliau of the Veneti, so that whichever lived longer would protect the young heir of the other. Upon Budic's death, however, Macliau invaded and annexed Cornouaille and then later martyring several of its members, including Ia of Cornwall; Saint Gwinear met with a similar fate, being thrown with his followers into a pit of reptiles.

After decades of exile, Tewdwr returned to Brittany and defeated Macliau and his oldest son Jacob in 577. He permitted Macliau's younger son Waroc to rule around Vannes.

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Important facts

Born
520
Birth century
Died
584
Also known as
King Teudur of Cornwall, King Theodoric of Cornouaille

Contemporaries

People whose lives overlapped Tewdwr Mawr's

Frequently asked questions

Who was Tewdwr Mawr?

Breton and Cornish king

When was Tewdwr Mawr born?

Tewdwr Mawr was born in 520.

When did Tewdwr Mawr die?

Tewdwr Mawr died in 584.

Sources & further reading

· Wikipedia: Tewdwr Mawr

· Wikidata: Q19665654

· DBpedia: Tewdwr Mawr

Cite this page

APA: Biography.guide. (2026). Tewdwr Mawr. https://biography.guide/tewdwr-mawr/

MLA: "Tewdwr Mawr." Biography.guide, https://biography.guide/tewdwr-mawr/.

Chicago: "Tewdwr Mawr." Biography.guide. https://biography.guide/tewdwr-mawr/.

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

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