Ukraine after the Russian Revolution
Various factions fought over Ukrainian territory after the collapse of the Russian Empire following the Russian Revolution of 1917 and after the First World War ended in 1918, resulting in the collapse of Austria-Hungary, which had ruled Ukrainian Galicia. The crumbling of the empires had a great effect on the Ukrainian nationalist movement, and in a short period of four years a number of Ukrainian governments sprang up. This period was characterized by optimism and by nation-building, as well as by chaos and civil war. Matters stabilized somewhat in 1921 with the territory of modern-day Ukraine divided between Soviet Ukraine (which would become a constituent republic of the Soviet Union in 1922) and Poland, and with small ethnic-Ukrainian regions belonging to Czechoslovakia and to Romania.