 After four years of warfare, the Red Army's defeat of Pyotr Nikolayevich Wrangel in the south in 1920
allowed the foundation of the Union of Soviet Socialist Republics in December 1922.Historian John Erickson sees 1 February 1924, when Mikhail Frunze became head of the Red Army staff, as marking the ascent of the general staff, which came to dominate Soviet military planning and operations.By 1 October 1924 the Red Army's strength had diminished to 530,000.