According to the saga "The Melody of the House of Buchet",[REF] Cormac married Eithne Táebfada, daughter of Cathaír Mór and foster-daughter of Buchet, a wealthy cattle-lord from Leinster whose hospitality was so exploited that he was reduced to poverty.
Cormac is credited with three sons, Dáire, Cellach and Cairbre Lifechair, and ten daughters.