During World War I, Russian-controlled Estonia proclaimed its independence on November 28, 1917, and immediately Bolshevik (Soviet) troops advanced to retake the country. However, to check the Bolsheviks, the Germans occupied Estonia (December 1917), which, under German defense, again declared it independence on February 24, 1918. By the Treaty of Brest-Litovsk, Germany forced Soviet Russia to give up the Baltic states (Estonia, Latvia, and Lithuania), but after Germany's defeat (November 11, 1918) and renunciation of the treaty, Soviet forces again invaded Estonia. The encountered fierce resistance by the Estonians, who were helped by a British flotilla in the Baltic, and were expelled in January 1919. An anti-Bolshevik army, assembled and led by Nikolai N. Yudenich (1862-1933), marched across the Estonian-Russian border in a valorous attempt to seize Petrograd (Leningrad) in October 1919. The Bolshevik leader Leon Trotsky (1879-1940), unnerved by this development, hastily gathered a motley army of
workers and soldiers, which was able to repulse Yudenich's troops and force their retreat to Estonia. Estonia's independence was officially recognized by the Soviet government by the Treat of Dorpat (Tartu) on February 2, 1920.