The Phoenix Park Murders were the stabbings on 6 May 1882 in the Phoenix Park in Dublin of Lord Frederick Cavendish and Thomas Henry Burke. Cavendish was the newly appointed Chief Secretary for Ireland, and Burke was the Permanent Undersecretary, the most senior Irish civil servant. The assassination was carried out by members of the "Irish National Invincibles".
Cavendish - who was married to Lucy Cavendish the niece of British Prime Minister William Ewart Gladstone, and had worked as Gladstone's personal secretary - had only arrived in Ireland the day he was murdered. He and Burke were attacked as they walked to the Viceregal Lodge, the "out of season" residence of the Lord Lieutenant of Ireland. Thomas Myles, resident surgeon at the nearby Dr Steevens' Hospital, was summoned to render medical assistance to the victims. The then Lord Lieutenant, Lord Spencer, described suddenly hearing screams, before witnessing a man running to the Lodge grounds shouting "Lord Frederick Cavendish and Mr. Burke are killed." Responsibility for the assassinations was claimed by a small hitherto unheard-of Republican organisation called the Irish National Invincibles.
The hunt for the perpetrators was led by Superintendent John Mallon, a Catholic who came from Armagh. Mallon had a pretty shrewd idea of who was involved. He suspected a number of former Fenian activists. A large number of suspects were arrested and kept in prison by claiming they were connected with other crimes. By playing off one suspect against another Mallon got several of them to reveal what they knew.
The Invincibles' leader, James Carey, and Michael Kavanagh agreed to testify against the others. Joe Brady, Michael Fagan, Thomas Caffrey, Dan Curley and Tim Kelly were convicted of the murder and were hanged by William Marwood in Kilmainham Gaol in Dublin between 14 May and 4 June, 1883. Others were sentenced to serve long prison terms.
Charles Stewart Parnell made a speech condemning the murders in 1882. This increased his already huge popularity in both Britain and Ireland. He had just enabled some reforms under the Kilmainham Treaty four days before the murders. Parnell's reputation increased in Ireland, being seen as a more moderate reformer who would never excuse such tactics.
However, Parnell's policy of allying his party to Gladstone's Liberal Party in 1886 to enable Home Rule was also ultimately defeated by the murders. Gladstone's Minister Lord Hartington was the elder brother of Lord Frederick Cavendish. Saddened and infuriated by the manner of his brother's early death, Hartington split with Gladstone on the Home Rule bills of 1886 and 1893 and led the breakaway Liberal Unionist Association which allied itself to Lord Salisbury's conservative governments. In the ensuing 1886 general election the Conservatives and Liberal Unionists swept the board. This delayed Home Rule by 28 years, until the Third Irish Home Rule Bill which was passed technically in 1914, but which was never effected.
In March 1887, The Times printed letters purportedly from Parnell claiming sympathy with the murderers and that his public denunciation of them was insincere. It emerged that the letters were forgeries written by journalist Richard Piggott, and Parnell was personally vindicated by the Parnell Commission in 1888-89.