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 confiscations 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.