Arthur Griffith (Irish: Art Ó Gríobhtha; 31 March 1872 – 12 August 1922) was the founder and third leader of Sinn Féin. He served as President of Dáil Éireann from January to August 1922, and was head of the Irish delegation at the negotiations in London that produced the Anglo-Irish Treaty of 1921.
Griffith was elected a Sinn Féin MP in the Cavan East by-election of mid-1918 when he asked William O'Brien to move the writ for his candidacy, and held the seat when Sinn Féin subsequently routed the Irish Parliamentary Party at the 1918 general election. In that election he was also returned for the seat of Tyrone North West.
Sinn Féin's MPs decided not to take their seats in the British House of Commons but instead set up an Irish parliament, Dáil Éireann; the Irish War of Independence followed almost immediately. The dominant leaders in the new unilaterally declared Irish Republic were figures like Éamon de Valera, President of Dáil Éireann (1919–21), President of the Republic (1921–1922), and Michael Collins, Minister for Finance, head of the IRB and the Irish Republican Army's Director of Intelligence.
During de Valera's absence in the United States (1919–21) Griffith served as Acting President and gave regular press interviews. He was imprisoned in December 1920 but was subsequently released on 30 June 1921.
Griffith became central to the Republic again when, in October 1921, President de Valera asked him to head the delegation of Irish plenipotentiaries to negotiate with the British government. The delegates set up Headquarters in Hans Place, London. After nearly 2 months of negotiations it was there, in private conversations, that the delegates finally decided to recommend the Treaty to the Dáil Éireann on 5 December 1921; negotiations closed at 2.20am on 6 December 1921. Griffith was the member of the treaty delegation most supportive of its eventual outcome, a compromise based on dominion status, rather than a republic. After the ratification by 64 votes to 57 of the Anglo-Irish Treaty by the Second Dáil on 7 January 1922, he replaced de Valera, who stepped down in protest as President of the soon-to-be abolished Irish Republic. A vote was held on 9 January to choose between Griffith or De Valera, which De Valera lost by 58 to 60. A second ratification of the Treaty by the House of Commons of Southern Ireland followed shortly afterwards. Griffith was, however, to a great extent merely a figurehead as President of the second Dáil Éireann and his relations with Michael Collins, head of the new Provisional Government were somewhat tense.
Suffering from overwork and strain after the long and difficult negotiations with the British government, and the work involved in establishing the Free State government, Griffith entered St. Vincent's Nursing Home, Dublin, during the first week of August 1922, following an acute attack of tonsilitis. He was confined to a room in St Vincent's by his doctors, who had observed signs of what they thought might be a subarachnoid hemorrhage, but it was difficult to keep him quiet, and he resumed his daily work in the government building. He had been about to leave for his office shortly before 10 am on 12 August 1922, when he paused to retie his shoelace and fell down unconscious. He regained consciousness, but collapsed again with blood coming from his mouth. Three doctors rendered assistance, but to no avail. Father John Lee of the Marist Fathers administered extreme unction, and Griffith expired as the priest recited the concluding prayer. The cause of death was reported as being due to heart failure. He died at the age of 50, ten days before Michael Collins' assassination in County Cork. He was buried in Glasnevin Cemetery four days later.