Брусиловский прорыв
During the First World War Ukraine was in the front lines of the main combatants: the Entente-allied Russian Empire and Romania, and the Central Powers of the German Empire and Austria-Hungary. By the start of 1917, after the Imperial Russian Army's Brusilov Offensive – strategically successful yet costly in terms of the army's manpower – the Tsar's forces held a front line which partially reclaimed Volhynia and eastern Galicia.