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Cathal mac Conchobair

d. 925

King of Connacht

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About Cathal mac Conchobair

Cathal mac Conchobair (died 925) was King of Connacht.

Family background

Cathal was the third son of Conchobar mac Taidg Mór (died 882) to rule Connacht, following his older brother Áed mac Conchobair (died 888) and youngest brother Tadg mac Conchobair (died 900). There may have been a fourth brother, Måel Cluiche mac Conchobair, who died in battle in 913.

They belonged to the SĂ­l Muiredaig branch of UĂ­ BriĂșin Ai kindred. The UĂ­ BriĂșin Ai claimed descent from Brion, an older brother of Niall of the Nine Hostages, and the kingship of Connacht alternated irregularly between the SĂ­l Muiredaig and the SĂ­l Cathail branches of the kindred. By Cathal's time, the SĂ­l Cathail were all but excluded from the succession.

King of Connacht

On becoming king, Cathal was faced with a demand from Flann Sinna (died 916), the High King of Ireland, for acknowledgement of his authority. This was agreed in a meeting at Clonmacnoise in 900, and Cathal is found frequently fighting alongside and on behalf of Flann.

The Munster Wars

War broke out between the high king and the King of Munster, Cormac mac CuilennĂĄin (died 908) and Cathal became caught up in this as an ally of Flann Sinna. In 907, the forces of Munster campaigned against the Connachta as far as Mag nAĂ­ (in central modern County Roscommon) and the Ui Neill and took the hostages of Connacht. These forces included a naval force operating on the Shannon. In 908, however, the forces of the high king which included Cathal defeated and crushed the forces of Munster at the Battle of Bellaghmoon in Mag Ailbe (Ballaghmoon, in northern modern County Carlow) and Cormac was slain.

Connacht invaded

In 913, Niall GlĂșndub (died 919) of the CenĂ©l nEĂłgain of the northern Ui Neill began to make his bid to be recognized as heir to the high Kingship. He invaded Connacht and defeated the men of North Connacht (UĂ­ Amalgada and the men of Umall). Cathal's brother was slain in this affair. Niall became high king in 916.

Defeat of Donnchad Donn

The next high king Donnchad Donn (died 944) of Meath invaded Connacht in 922. His forces were however defeated in the wilderness of Áth Luain (Athlone). Whether this was the usual attempt of a new high king to impose his authority on Connacht or directed against the intense Viking activity on the Shannon at this time is not mentioned. The King of Aidne, Mael son of Duí had been killed by Vikings that year This same Indrechtach was found operating a fleet with the men of Meath on Loch Derg clearing out the Munster fleet from the Shannon.

Death and succession

Cathal died in 925 in penitence. Cathal was succeed on his death by his son Tadg in TĂșir (died 956), who was succeeded in his turn by Fergal ua Ruairc (died 967) of the rising UĂ­ BriĂșin BrĂ©ifne branch of the UĂ­ BriĂșin.

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Important facts

Died
925

Frequently asked questions

Who was Cathal mac Conchobair?

King of Connacht

When did Cathal mac Conchobair die?

Cathal mac Conchobair died in 925.

Sources & further reading

· Wikipedia: Cathal mac Conchobair

· Wikidata: Q2941775

· DBpedia: Cathal mac Conchobair

Cite this page

APA: Biography.guide. (2026). Cathal mac Conchobair. https://biography.guide/cathal-mac-conchobair/

MLA: "Cathal mac Conchobair." Biography.guide, https://biography.guide/cathal-mac-conchobair/.

Chicago: "Cathal mac Conchobair." Biography.guide. https://biography.guide/cathal-mac-conchobair/.

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

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