correlation with genome-wide homozygosity likely reflects the serial founder effect that was initiated with the ancient successive out-of-Africa migrations. This does not necessarily mean that these events (north-ward migration and evolutionary selection pressures) took place within the borders of the Netherlands; it could also be that Southern Europeans have migrated more to the South of the Netherlands, and/or Northern Europeans more to the Northern parts. The north–south differences were likely maintained by the relatively strong segregation of the Catholic South and the Protestant North during the last centuries. During the last 50 years or so there was a large increase of non-religious individuals in the Netherlands. Their spouses are more likely to come from a different genetic background than those of religious individuals, causing non-religious individuals to show lower levels of genome-wide homozygosity than Catholics or Protestants. Dutch diaspora Since World War II, Dutch emigrants have mainly departed the Netherlands for Canada, the Federal Republic of Germany, the United States, Belgium, Australia, and South Africa, in that order. Today, large Dutch communities also exist in the United Kingdom, France, Spain, Turkey, and New Zealand. Central and Eastern Europe During the German eastward expansion (mainly taking place between the 10th and 13th century), a number of Dutchmen moved as well. They settled mainly east of the Elbe and Saale rivers, regions largely inhabited by Polabian Slavs. After the capture of territory along the Elbe and Havel Rivers in the 1160s, Dutch settlers from flooded regions in Holland used their expertise to build dikes in Brandenburg, but also settled in and around major German cities such as Bremen and Hamburg and German regions of Mecklenburg and Brandenburg. From the 13th to the 15th centuries, Prussia invited several waves of Dutch and Frisians to settle throughout the country, mainly along the Baltic Sea coast. In the early-to-mid-16th century, Dutch Mennonites began to move from the Low Countries (especially Friesland and Flanders) to the Vistula delta region, seeking religious freedom and exemption from military service. The territories which they settled were located in the autonomous province of Polish Prussia in the Polish–Lithuanian Commonwealth, what is contemporary northern Poland. These communities became known as the Olęders, a Polish rendering of the term Hollander. After the partitions of Poland, the Prussian authorities took over and its government eliminated exemption from military service on religious grounds. The Dutch Mennonites also migrated as far as the Russian Empire,