The Ukrainian Army had its roots in the period of the Ukrainian Central Rada
(March 1917–January 1918), partly through the detachment of Ukrainian units from the Russian Army (the Haidamak Cavalry regiment on the Western front, the three Shevchenko Regiments at Moscow, etc.), partly through the Ukrainization of Russian Army units, and partly (after November 1918) through the formation of new units from former units of the Austro-Hungarian Army (e.g., the Ukrainian Sich Riflemen). In part, these developments were spontaneous, but also influential were the All-Ukrainian Military Congresses (of Ukrainian soldiers’ committees), which convened at Kiev (on 18–21 May, 18–23 June and 2–12 November 1917) and called for the establishment of a separate Ukrainian army. The Central Rada, however, was dominated by socialists and was initially opposed to a standing army; it developed, instead, the idea of the Free Cossacks, whose position as a national militia was defined by the Rada on 13 November 1917. The invasion of Ukraine by Soviet forces under V. A. Antonov-Ovseenko in December 1917, marking the beginning of the Soviet–Ukrainian War, changed the Rada’s mind, but it was overthrown before much could be done. By April 1918, the Ukrainian Army consisted of the Zaporozhian Corps (four infantry regiments, one cavalry regiment, and two light artillery), the Sich Riflemen, the Bluecoats (formed from Ukrainian POWs in German camps), and the Greycoats (formed from Ukrainian POWs in Austrian camps), which were in the process of formation, and an indeterminate number of Free Cossacks, totaling approximately 15,000 men (of whom 2,000 were cavalry).After the First All-Ukrainian Military Congress, the command of the Ukrainian Army was placed in the hands of the Ukrainian General Military Committee, headed by Symon Petliura
, who became head of the General Secretariat of Military Affairs following the proclamation of the UNR on 20 November 1917 (and who remained the most important Ukrainian military leader throughout the civil-war period). The assistance of German and Austrian forces secured by the Treaty of Brest-Litovsk (27 January 1918) allowed this command to expel Soviet forces from most of Ukraine in March–April 1918, but the price extracted by the occupying forces was a heavy one: the German command demanded that Ukrainian forces abandon Crimea (which it did not recognize as belonging to the UNR), and on the eve of the coup of Hetman P. P. Skoropadskii, moved to reduce the army of the UNR to the Zaporozhian Corps alone, as the Bluecoats and the Sich Riflemen were disarmed by forces of the Austro-German intervention.During the period of the Hetmanate (or Ukrainian State
), a law on universal military service was promulgated (24 July 1918), with the aim of raising an army of 310,000 men. A decree of 16 October 1918 further determined that the army would be organized along Cossack lines, with territorial units (of seven regiments each) led by commanders (otamans) subordinate to one hetman. However, the resistance of both Russian officers in the army and the German high command limited the army’s development, and by the time of the collapse of the Skoropadskii regime in November–December 1918, the force numbered only some 60,000 men. (Characteristic was the abrogation of all Ukrainian army regulations on 11 November 1918 by the Russian General F. A. Keller, whom Skoropadskii had placed in command of the army.)