Tadhg na Mainistreach Mac Carthaigh Mór

Tadhg na Mainistreach Mac Carthaigh Mór reigned as King of Desmond from 1390/2 to his death in 1428. He was the son of the previous king Domhnall Óg Mac Carthaigh Mór (r. 1359–1390/2). According to the Annals of Inisfallen Tadhg Mac Carthaigh had the reputation as the greatest wine-drinker in Ireland when he died, but was still "a son worthy of his father". after which the title King of Desmond was rarely used by later members of the dynasty, the title of Mac Carthaigh Mór (Prince of Desmond) becoming the preferred.

After dying in Ballycarbery Castle, Tadhg was buried in the monastery there, while his wife Sebán died in Caislén Mac nAeducáin and was buried at Tralee.

His epithet "na Mainistreach" means "of the monastery."