The German Empire conquered Ukraine during World War I and was planning on either annexing it or installing a puppet king, but was defeated by the Entente, with major involvement by the Ukrainian Bolsheviks. After conquering the rest of Ukraine from the <answer>Whites</answer>, Ukraine joined the USSR and was enlarged (gaining Crimea and then Eastern Galicia), whence a process of Ukrainization was begun, with encouragement from Moscow.
Who did the Ukrainian Bolsheviks conquer the Ukraine from?
Whites