 Complete the following phrase:  During World War II, on 10 May 1940, at the time when Belgium was being invaded, Prince Albert, his elder sister Princess Joséphine-Charlotte and his elder brother Prince Baudouin, left the country for France and later Spain. The Prince and the Princess returned to Belgium on 2 August 1940. They continued their studies until 1944, either at Laeken, or at the Castle of Ciergnon in the Ardennes. In June 1944, at the time of the 