After 74 days on hunger strike in Brixton Prison, England, the Sinn Féin Lord Mayor of Cork, Terence MacSwiney dies.

Sinn Fin ( shin FAYN, Irish: [n fen]; English: "[We] Ourselves") is an Irish republican and democratic socialist political party active throughout both the Republic of Ireland and Northern Ireland.

The original Sinn Fin organisation was founded in 1905 by Arthur Griffith. Its members founded the revolutionary Irish Republic and its parliament, the First Dil, during the Irish War of Independence. The party split in the aftermath of the Irish Civil War, giving rise to the two traditionally dominant parties of southern Irish politics: Fianna Fil, and Cumann na nGaedheal (which became Fine Gael). For several decades the remaining Sinn Fin organisation was small without parliamentary representation. Another split in 1970 at the start of the Troubles led to the Sinn Fin of today, with the other faction eventually becoming the Workers' Party.

During the Troubles, Sinn Fin was associated with the Provisional Irish Republican Army (IRA). For most of that conflict, there were broadcasting bans on Sinn Fin in the Irish media and in the British media. Although the party sat on local councils, it had a policy of abstentionism for the British House of Commons and the Irish Dil ireann, standing for election to those parliaments but vowing not to take their seats if elected. After Gerry Adams became party leader in 1983, electoral politics were prioritised increasingly. In 1986, the party dropped its abstentionist policy for the Dil; some members formed Republican Sinn Fin in protest. In the 1990s, Sinn Finunder the leadership of Adams and Martin McGuinnesswas involved in the Northern Ireland peace process, which led to the Good Friday Agreement and created the Northern Ireland Assembly. In 2006, it co-signed the St Andrews Agreement and accepted the role of the Police Service of Northern Ireland.

Sinn Fin is the largest party in the Northern Ireland Assembly, having won the largest share of first-preference votes and the most seats in the 2022 election, the first time an Irish nationalist party has done so. From 2007 to 2022 it was the second-largest party in the Assembly, after the Democratic Unionist Party (DUP), and its members served as deputy First Minister in the power-sharing Northern Ireland Executive. In the UK House of Commons, Sinn Fin holds seven of Northern Ireland's seats; there, it continues to abstain from parliament. In Dil ireann it is the joint-largest party and is the main opposition, having won the largest share of first-preference votes in the February 2020 election. The current party president is Mary Lou McDonald, who succeeded Gerry Adams in 2018.

A hunger strike is a method of non-violent resistance in which participants fast as an act of political protest, or to provoke a feeling of guilt in others, usually with the objective to achieve a specific goal, such as a policy change. Most hunger strikers will take liquids but not solid food.

In cases where an entity (usually the state) has or is able to obtain custody of the hunger striker (such as a prisoner), the hunger strike is often terminated by the custodial entity through the use of force-feeding.