Mathghamhain Maonmhaighe Ó Briain, King of Thomond, 1360-69.
Mathghamhain was the son of Muichertach O'Brien King of Thomond and was preceded by his uncle Dairmaid macToirdelbaig O'Brien.
His son Brian Sreamhach MacMathghamhna O'Brien succeeded him as King of Thomond. He died in 1369 and was buried in Ennis Abbay, County Clare, Ireland.
His nickname, Maonmhaighe, derived from his foster-home.
References
Mathghamhain Maonmhaighe Ó Briain Wikipedia(Text) CC BY-SA