In the summer of 1919, Denikin led the assault of the southern White forces in their final push to capture Moscow . For a time, it appeared that the White Army would succeed in its drive; Leon Trotsky, as the supreme commander of the Red Army, hastily concluded an agreement with Nestor Makhno's anarchist "Revolutionary Insurrectionary Army of Ukraine" (the 'Black Army') for mutual support. Makhno duly turned his Black Army east and led it against Denikin's extended lines of supply, forcing the Whites to retreat. Denikin's army would be decisively defeated at Orel in October 1919, some 360 km south of Moscow. The White forces in southern Russia would be in constant retreat thereafter, eventually reaching the Crimea in March 1920.