Dermot mac Tadhg Mor, 7th king of Moylurg, reigned from 1124 to 1159.
Vassal and kinsman of the O Conchobhair Kings of Connacht.
Dermot was the progenitor of the MacDermot family, as well as its offshoot septs such as MacDermot Roe, McDonagh, and Crowley (surname).
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