Following 9 April 1940, when Norway was invaded and subsequently occupied by Nazi Germany, Stockholm became an important city for Norwegian politics. Wollebæk had refused to obey the orders of Vidkun Quisling—who during the German invasion declared a Fascist coup d'état—and the Norwegian legation in Stockholm was soon reinforced with additional personnel. Jens Bull, the highest-ranking civil servant in the Ministry of Foreign Affairs, was sent to Stockholm, and the Norwegian government-in-exile, once secure in London, sent its representatives. Wollebæk participated in negotiations in the summer of 1940, but at the same time he fell ill. He died in October 1940, being succeeded by Jens Bull. Before the war ended, more than 50,000 Norwegians had fled to Sweden.