Furthermore, a sizable portion of Russia's ethnic Germans migrated into Russia from its Polish possessions. The 18th-century partitions of Poland (1772–1795) dismantled the Polish-Lithuanian state, dividing it between Austria, Prussia and Russia. Many Germans already living in those parts of Poland transferred to Russia, dating back to medieval and later migrations. Many Germans in Congress Poland migrated further east into Russia between then and World War I, particularly in the aftermath of the Polish insurrection of 1830. The Polish insurrection in 1863 added a new wave of German emigration from Poland to those who had already moved east, and led to the founding of extensive German colonies in Volhynia. When Poland reclaimed its independence in 1918 after World War I, it ceased to be a source of German emigration to Russia, but by then many hundreds of thousands of Germans had already settled in enclaves across the Russian Empire.