The occupation of Smyrna by Greece on 18 May 1919 triggered a nationalist movement to rescind the terms of the treaty. Turkish revolutionaries led by Mustafa Kemal Atatürk, a successful Ottoman commander, rejected the terms enforced at Sèvres and under the guise of General Inspector of the Ottoman Army, left Istanbul for Samsun to organize the remaining Ottoman forces to resist the terms of the treaty. On the eastern front, after the invasion of Armenia in 1920 and signing of the Treaty of Kars with the Russian S.F.S.R. Turkey took over territory lost to Armenia and post-Imperial Russia.