First World War, the revolutions and aftermath
When World War I and series of revolutions across the Europe including the October Revolution in Russia shattered or crippled many existing empires such as the Austrian and Russian ones, while people of Ukraine were caught in the middle. Between 1917 and 1918, several separate Ukrainian republics manifested independence, the anarchist Free Territory, the Ukrainian People's Republic, the West Ukrainian People's Republic, and numerous Bolshevik revkoms.
As the area of Ukraine fell into warfare and anarchy, it was also fought over by German and Austrian forces, the Red Army of Bolshevik Russia, the White Forces of General Denikin, anarchists led by Nestor Makhno. Kiev itself was occupied by different armies. The city was captured by the Bolsheviks on February 9, 1918 then by the Germans on March 2, 1918. Two days later, the Bolsheviks signed the Treaty of Brest-Litovsk, which formally ended hostilities on the Eastern Front of World War I and left Ukraine in a German sphere of influence.
Yet disturbances continued throughout Eastern Ukraine, where local Bolsheviks, Greens, and the anarchist Revolutionary Insurrectionary Army of Ukraine refused to subordinate to Germany. Former Russian Army General Pavlo Skoropadsky led a successful German-backed coup against the Rada on April 29. He proclaimed the conservative Hetmanate, and reversed many of the policies of the former government. The new government had close ties to Berlin, but Skoropadsky never declared war on any of the Triple Entente powers; Skoropadsky also placed Ukraine in a position that made it a safe haven for many upper- and middle-class people fleeing Bolshevik Russia, and was keen on recruiting many former Russian Army soldiers and officers. Despite sporadic harassment from Makhno, the Hetmanate enjoyed relative peace.
The Ukrainian national idea continued during the inter-war years and was even spread to a large territory with traditionally mixed population in the east and south that became part of the Ukrainian State. The Ukrainian culture even enjoyed a revival due to German concessions that ensured further Ukrainian loyalty. In these years, an impressive Ukrainization program was implemented throughout the hetmanate.
The rapidly developed Ukrainian language based education system dramatically raised the literacy of the Ukrainophone rural population. Simultaneously, the newly-literate ethnic Ukrainians migrated to the cities, which became rapidly largely Ukrainianised—in both population and in education. Similarly expansive was an increase in Ukrainian language publishing and overall eruption of Ukrainian cultural life.
At the same time, the usage of Ukrainian was continuously encouraged in the workplace and in the government affairs as the recruitment of indigenous cadre was implemented as part of the korenisation policies. While initially, the party and government apparatus was mostly Russian-speaking. The Ukrainian national Orthodox church was created called the Ukrainian Autocephalous Orthodox Church (UAOC).
The change in the economic policies towards the fast-pace industrialisation was marked by the 1928 introduction of a five-year plan matching the plan used by the Soviet Union. The industrialisation brought about a dramatic economic and social transformation in traditionally agricultural Ukraine. In the plan the industrial output of Ukraine quadrupled as the nation underwent a record industrial development. The massive influx of the rural population to the industrial centres increased the urban population from 19% to 34%.