The Mongolian invasion of 1241 inflicted casualties in Silesia, limited to a narrow strip from Opole to Wrocław and Legnica. The time after 1241 was marked by a strong expansion of German settlement activities, mostly carried out by people from older German places in Silesia. Colonization affected the mountains in the south of Lower and Middle Silesia, the Lower and Middle Silesian regions to the right of the Oder and Upper Silesia. During the time many Polish places received German law, often with the help of German settlers.