From the latter half of the 1930s, Nazi Germany made increasingly aggressive territorial demands, threatening war if these were not met. The Saarland voted by plebiscite to rejoin Germany in 1935, and in 1936 Hitler sent troops into the Rhineland, which had been de-militarized after World War I. Germany seized Austria in the "Anschluss" of 1938, and demanded and received the Sudetenland region of Czechoslovakia in that same year. In March 1939, the Slovak state was proclaimed and became a client state of Germany, and the German Protectorate of Bohemia and Moravia was established on the remainder of the occupied Czech Lands. Shortly after, Germany pressured Lithuania into ceding the Memel Territory. Germany signed a non-aggression pact with the Soviet Union and invaded Poland on 1 September 1939, launching World War II in Europe. By early 1941, Germany and their European allies in the Axis powers controlled much of Europe. Extended offices of the "Reichskommissariat" took control of Nazi-conquered areas and a German administration was established in the remainder of Poland. Germany exploited the raw materials and labour of both its occupied territories and its allies.