Tomás Láidir Mac Coisdealbhaigh

Tomás Láidir Mac Coisdealbhaigh, Irish soldier and poet, fl. 1660s.

Tomás Láidir Mac Coisdealbhaigh was a member of the Costello family of north Connacht who lost their lands in the Cromwellian confications of the 1650s. He was a descendant of Sir William de Angulo, who died in 1206. His brother was the Rapparee, Colonel Dubhaltach Caoch Mac Coisdealbhaigh.

Mac Coisdealbhaigh was in love with Úna Ní Dhiarmaida but her family refused to allow them to marry. After several attempts, Mac Coisdealbhaigh made a last formal proposal, swearing that if he crossed Áth na Donóige (a ford on the Donóige river) on his way home without receiving an answer, he would never marry Úna. "He rode slowly and waited a long time in the ford itself, but finally on the mocking advice of his own servant, he crossed to the opposite bank. A messenger came soon after with news that he had been accepted, but he refused to go back on his oath. Úna died shortly afterward. Tomás killed the servant who gave him the evil counsel, and composed the famous song Úna Bhán."

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