The Ulster Unionist Party (UUP) is a unionist political party in Northern Ireland. The UUP is the third oldest political party in the United Kingdom, and the oldest political party in Ireland. The party was founded as the Ulster Unionist Council on 3 March 1905, emerging from the Irish Unionist Alliance in Ulster. Under Sir Edward Carson, it led unionist opposition to the Irish Home Rule movement. Following the partition of Ireland, it was the governing party of Northern Ireland between 1921 and 1972. It was supported by most unionist voters throughout the conflict known as the Troubles, during which time it was often referred to as the Official Unionist Party (OUP).