The Council of People's Commissars set up the Red Army by decree on January 15, 1918 (Old Style) (January 28, 1918), basing it on the already-existing Red Guard. The official Red Army Day of February 23, 1918 marked the day of the first mass draft of the Red Army in Petrograd and Moscow, and of the first combat action against the rapidly advancing Imperial German Army. February 23 became an important national holiday in the Soviet Union, later celebrated as "Soviet Army Day", and it continues as a day of celebration in Russia as Defenders of the Motherland Day. Credit as the founder of the Red Army generally goes to Leon Trotsky, the People's Commissar for War from 1918 to 1924.