Derry City Council (; Ulster-Scots: Derry Cittie Cooncil) was the local government authority for the city of Derry in Northern Ireland. It merged with Strabane District Council in April 2015 under local government reorganisation to become Derry and Strabane District Council. The council provided services to nearly 108,000 people, making it the third-largest of the then 26 district councils in Northern Ireland by population. The council was made up of 30 councillors, elected every four years from five electoral areas and held its meetings in The Guildhall. The mayor for the final 2014–2015 term was Brenda Stevenson of the Social Democratic and Labour Party, with Gary Middleton of the Democratic Unionist Party serving as deputy mayor. History Londonderry City Council became Derry City Council in 1984 when it changed the name of the district it governed. The city itself retained the name "Londonderry". (See Derry/Londonderry name dispute.) The district was formed in 1973 under the Local Government (Boundaries) Act (Northern Ireland) 1971 and the Local Government Act (Northern Ireland) 1972 by merging Londonderry county borough and Londonderry rural district, which had been jointly administered since 1969 by the unelected Londonderry Development Commission. The rural district covered an area around the county borough, roughly corresponding to the baronies of Tirkeeran and North West Liberties of Londonderry. The Development Commission, formed with the aim of creating a "new town", replaced both Londonderry Corporation, which had run the city since 1613, and Londonderry Rural District Council, which dated from the Local Government (Ireland) Act 1898. Coat of arms and motto The devices on the city's arms are a skeleton and a three-towered castle on a black field, with the chief or top third of the shield depicting the arms of the City of London: a red cross and sword on white. In the centre of the cross is a gold harp. The blazon of the arms is as follows: Sable, a human skeleton Or seated upon a mossy stone proper and in dexter chief a castle triple towered argent on a chief also argent a cross gules thereon a harp or and in the first quarter a sword erect gules According to documents in the College of Arms in London and the Office of the Chief Herald of Ireland in Dublin, the arms of the city were confirmed in 1613 by Daniel Molyneux, Ulster King of Arms. The College of Arms document states