Sinn Féin is a left-wing Irish republican political party active in both the Republic of Ireland and Northern Ireland. Sinn Féin are also the only party that may be elected to the Oireachtas, Northern Ireland Executive & Westminster.
The original Sinn Féin organisation was founded on November 28, 1905 by Arthur Griffith. It took its current form on January 17, 1970 after a split within the party (with the other side becoming the Workers’ Party of Ireland) and has historically been associated with the Provisional Irish Republican Army (IRA).
Sinn Féin is the largest nationalist party in the Northern Ireland Assembly, and the joint-largest overall (alongside the Democratic Unionist Party); it had four ministerial posts in the most recent power-sharing Northern Ireland Executive. It holds seven of Northern Ireland’s 18 seats—the second-largest bloc after the Democratic Unionist Party (DUP)—at Westminster, where it follows a policy of abstentionism, refusing to attend parliament or vote on bills. It is the third-largest party, and the largest party on the left, in the Oireachtas, the parliament of the Republic of Ireland.