Lord Frederick Charles Cavendish (born Nov. 30, 1836, Eastbourne, Sussex, Eng.—died May 6, 1882, Dublin, Ire.) was a British politician, protégé of William Ewart Gladstone, who was murdered by Fenian extremists the day after his arrival in Dublin as chief secretary of Ireland and as a goodwill emissary from England, at the height of the Irish crisis in 1882.
The second son of the 7th duke of Devonshire, Cavendish entered Parliament in 1865. The year before, he had married Mrs. Gladstone’s niece, Lucy, daughter of the 4th Baron Lyttelton. Gladstone came to admire and trust Cavendish, especially after taking him as private secretary in 1872, and looked to him as a future leader of the parliamentary Liberal Party. He was financial secretary to the Treasury from 1880 and, as such, was the right-hand man of Gladstone, chancellor of the Exchequer as well as prime minister.
In 1882 Gladstone asked him to undertake the thankless and dangerous office of chief secretary for Ireland. Cavendish crossed to Dublin on the night of May 5. The following evening, he walked across Phoenix Park with Thomas H. Burke, the permanent undersecretary for Ireland. Burke was attacked by a Fenian splinter group armed with knives, Cavendish tried to defend him, and both were killed. Five of their assassins, members of a secret society called the Invincibles, were betrayed and hanged in 1883; several others were sentenced to long prison terms. (See Phoenix Park murders.)