Nazi Germany terminated the Non-Aggression Pact signed by Joachim von Ribbentrop and Vyacheslav Molotov with its invasion of the Soviet Union at 3:15 am on June 22, 1941. Large areas of the European part of the Soviet Union would be placed under German occupation between 1941 and 1944. Soviet collaborators included numerous Russians and members of other ethnic groups.
The Germans attempted to recruit Soviet citizens (and to a lesser extent other Eastern Europeans) voluntarily for the OST-Arbeiter or Eastern worker program; originally this worked, but the news of the terrible conditions they faced dried up the volunteers and the program became forcible.
Before World War II, Ukraine was divided primarily between the Ukrainian SSR of the Soviet Union and the Second Polish Republic. Smaller regions were administered by Romania and Czechoslovakia. Only the Soviet Union recognised Ukrainian autonomy, and large numbers of Ukrainians, particularly from the East, fought in the Red Army.
The negative impact of Soviet denationalisation policies implemented in the 1930s were still fresh in the memory of Ukrainians. These included the Holodomor of 1933, the Great Terror, the persecution of intellectuals during the Great Purge of 1937-38, the massacre of Ukrainian intellectuals after the annexation of Western Ukraine from Poland in 1939, the introduction and implementation of Collectivisation.
As a result, the population of whole towns, cities and villages, greeted the Germans as liberators which helps explain the unprecedented rapid progress of the German forces in the occupation of Ukraine.
Even before the German invasion, the Nachtigall and Roland battalions were set up and trained as Ukrainian battalions in the Wehrmacht, and were part of the initial invading force.
With the change in regime ethnic, Ukrainians were allowed and encouraged to work in administrative positions. These included and the auxiliary police, post office, and other government structures; taking the place of Poles, Russians and Jews.
Ostlegionen (literally "Eastern Legions") or Osttruppen ("Eastern Troops") were conscripts and volunteers from the occupied eastern territories recruited into the German Army of the Third Reich during the Second World War.
The staff of the disbanded 162nd Infantry Division in Poland was charged with the raising and training of the six Eastern Legions. It eventually raised and trained 82 battalions. A total of 98 battalions were raised with 80 serving on the Eastern Front and in the Balkans. 12 were later transferred to France and Italy in 1943