Diarmait mac Mael na mBo
d. 1072
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About
Diarmait mac Mael na mBo (killed 7 February 1072), King of Leinster, was the most powerful ruler in Ireland in his day; the annals style him ri Erenn co fressabra, 'King of Ireland with opposition'. First of the long-excluded Ui Cheinnselaig of Ferns to retake the Leinster kingship in centuries, he ruled Dublin through his son, and after Hastings he sheltered the fugitive sons of King Harold of England when they fled to Ireland. He fell in battle against the men of Meath at Odba. His father Donnchad Mael na mBo and four more annal-attested kings of Ui Cheinnselaig now stand above him, back to Cairpre mac Diarmata (died 876).
Research notes
*** UPDATE - READ FIRST (8 Oct 2026): the FRONTIER below has been PUSHED UP - his father Donnchad Mael na mBo (I100816) and the spine to Cairpre mac Diarmata d.876 (I100821) are now wired (Ui Cheinnselaig spine audit; grades ✓ to ~); the frontier statement in the layer below is superseded - the honest ceiling now sits on I100821. *** ✓ ANNAL-ATTESTED (AU obit, killed 7 Feb 1072 at Odba by Conchobor ua Mael Sechnaill; 'ri Erenn co fressabra' contemporary; Connacht campaign 1067; Harold's sons sheltered 1068/9 - standard accounts, web-verified 8 Oct 2026). FRONTIER: his father MAEL NA MBO and the Ui Cheinnselaig ascent (to Enna Cennselach) NOTE-ONLY, not wired. ⚠ His wife Derbforgaill (d.1080), granddaughter of BRIAN BORU, is NOT proven the mother of Murchad - do not harden. (CORRECTED 8 Oct 2026, user's catch: Brian Boru is ALREADY a direct ancestor at g32 via the Thomond O'Briens, I99632; the unproven maternity would only add a SECOND road to him, not admit him.) Wired 8 Oct 2026.