After the outbreak of the German-Soviet War in 1941, the area of eastern Lithuania was quickly seized by the Wehrmacht. On 27 May 1942 a new census was organised by the German authorities and the local Lithuanian collaborators. The details of the methodology used are unknown and the results of the census are commonly believed to be an outcome of the racial theories and beliefs of those who organised the census rather than the actual ethnic and national composition of the area. Among the most notable features is a complete lack of data on the Jewish inhabitants of the area (see Ponary massacre for explanation) and a much lowered number of Poles, as compared to all the earlier censuses.