Brian mac Maelruanaidh (died 1003) was King of Maigh Seóla.
All that is known for certain of Brian is contained in his obit, dated 1003: Brian, son of Maelruanaidh, lord of West Connaught, was slain by his own people In that year, "the Ui-Fiachrach Aidhne aided by West Connaught fought a battle against the Uí Maine" and "the men of West Meath ... wherein fell Gillaceallaigh, son of Comhaltan Ua Cleirigh, lord of Ui-Fiachrach; Conchobhar, son of Ubban; Ceannfaeladh, son of Ruaidhri, and many others.
Finn, son of Marcan, Tanist of Ui-Maine, fell in the heat of the conflict."
Both the Muintir Murchada and Uí Fiachrach Aidhne were allied with Brian Boru, who was the son of a daughter of Urchadh mac Murchadh.
This biography of a member of an Irish royal house is a stub.