The abolition of the Ottoman Sultanate by the Grand National Assembly of Turkey (GNAT) on 1 November 1922 ended the Ottoman Empire, which had lasted since 1299. On 11 November 1922, at the Conference of Lausanne, the sovereignty of the GNAT exercised by the Government in Ankara over Turkey was recognized. The last sultan, Mehmed VI, departed the Ottoman capital, Istanbul, on 17 November 1922. The legal position was solidified with the signing of Treaty of Lausanne on 24 July 1923.