O'Callaghan family, Barons Lismore of Shanbally and Viscounts Lismore of Shanbally

Cornelius O'Callaghan (1740/41-1797) was an MP for Fethard between 1761 and 1785. In 1774 he married Frances Ponsonby. In 1785, he was created 1st Baron Lismore of Shanbally, county Tipperary. His eldest son, Cornelius O'Callaghan (1775-1857) was appointed Privy Counsellor of Ireland in 1835 and also held the office of Lord Lieutenant of county Tipperary from 1851 to 1857. He was created Viscount Lismore of Shanbally in 1806. Two year later, he married Lady Eleanor Butler, daughter of John Butler, 17th Earl of Ormonde. He was succeeded by his only surviving son, George Ponsonby O'Callaghan (1815-1898), as 2nd Viscount Lismore. The title became extinct upon the 2nd Viscount's death, his two sons having predeceased him. The family seat, Shanbally Castle, passed to his cousins, Constance and Beatrice Butler, daughters of the 3rd Marquess of Ormonde.