Original sentence: In Polish istoriography massacres of Poles in Volhynia and Eastern Galicia (, literally: Volhynian slaughter) were part of an ethnic cleansing operation carried out in Nazi German-occupied Poland by the Ukrainian Insurgent Army (UPA)'s North Command in the regions of Volhynia (Reichskommissariat Ukraine) and their South Command in Eastern Galicia (General Government) beginning in March 1943 and lasting until the end of 1944
Edited sentence: In Polish istoriography massacres of Poles in Volhynia and Eastern Galicia (, literally: Volhynian slaughter; , Volyn tragedy) were part of an ethnic cleansing operation carried out in Nazi German-occupied Poland by the Ukrainian Insurgent Army (UPA)'s North Command in the regions of Volhynia (Reichskommissariat Ukraine) and their South Command in Eastern Galicia (General Government) beginning in March 1943 and lasting until the end of 1944