During World War II, Włocławek was occupied by German troops, which entered the city on 14 September 1939. Under the Nazi German occupation Włocławek was again renamed Leslau, annexed by decree to the German Reich on 8 October 1939 and administered from 26 October as a part of Reichsgau Posen (renamed on 29 January 1940 Reichsgau Wartheland).