sentences:  Polish activists were increasingly persecuted since 1937.An attack on a radio station in Gleiwitz on 31 August 1939, staged by the German secret police, served as a pretext, devised by Reinhard Heydrich under orders from Hitler, for Nazi Germany to invade Poland, which marked the start of the Second World War.After the invasion of Poland, the assets of local Polish banks were confiscated by Germany.