In 1940 the entire royal family had to flee Oslo because of the German invasion. It was deemed safer for the family to split up. The King and Crown Prince Olav would remain in Norway and the Crown Princess was to make her way to Sweden with the three children. The latter party reached Sweden on the night of 10 April, but although Crown Princess Märtha was Swedish-born, they encountered problems at the border station. According to Princess Astrid and others who were present, they were admitted only after the driver threatened to ram the border gate. Another account does not describe the escape so dramatically. However, when the King and Crown Prince inquired of Swedish foreign minister Christian Günther whether they could sleep one night in Sweden without being interned, they were denied.