The Battle of Grand Gulf was fought on April 29, 1863, during th: The devolved form of government in Northern Ireland is based on the 1998 Good Friday Agreement, which brought to an end a 30-year period of unionist-nationalist communal conflict known as The Troubles. The Agreement was confirmed by referendum and implemented later that year. It established power sharing arrangements for a devolved government and legislature, referred to as the Executive and Assembly respectively.[212] Elections to the Assembly use the single transferable vote system. The Executive and Assembly have powers similar to those devolved to Scotland.[citation needed] The Executive is led by a diarchy representing unionist and nationalist members of the Assembly.[213]  The First Minister and deputy First Minister of Northern Ireland are the joint heads of government of Northern Ireland.[214][215] Local government in Northern Ireland since 2015 has been divided between 11 councils with limited responsibilities.[192]