Norway was invaded by the Nazis on April 9, 1940. Within two months, the Nazis had crushed Norwegian military resistance and installed a puppet government. Norwegians responded to the occupation of their country both nonviolently and violently. Because of the unprovoked aggression that the Nazis unleashed upon them, many Norwegians felt that all forms of resistance were fully legitimate. However, most saw nonviolent resistance as the only practical option, given the massive military advantage of the occupying military forces.