During World War II Zhytomyr and the surrounding territory was, for two and a half years (first from July 9, 1941 to November 12, 1943 and again from November 19, 1943 to December 31, 1943) under Nazi German occupation and was Heinrich Himmler's Ukrainian headquarters. The Nazi regime in what they called the "Zhytomyr General District" became what historian Wendy Lower describes asa laboratory for… Himmler's resettlement activists… the elimination of the Jews and German colonization of the East—transformed the landscape and devastated the population to an extent that was not experienced in other parts of Nazi-occupied Europe besides Poland. [While]… [u]ltimately, the exigencies of the war effort and mounting partisan warfare behind the lines prevented Nazi leaders from fully developing and realizing their colonial aims in Ukraine… In addition to the immediate destruction of all Jewish communities, Himmler insisted that the Ukrainian civilian population be brought to a 'minimum.'