Foreign relations of Belgium sanctioned the creation of Belgium in 1831 on the condition that the country remain strictly neutral. This policy of neutrality ended after the experience of German occupation during World War I. In the years preceding World War II, Belgium tried to return to a policy of neutrality, but once again, Germany invaded the country. In 1948, Belgium signed the Treaty of Brussels with the United Kingdom, France, the Netherlands, and Luxembourg, and one year later became one of the founding members of the Atlantic Alliance. The Belgians have been strong advocates of European integration, and most aspects of their foreign,
France–Germany relations the mood in France, and plunged Germany into economic hardship and violent internal convulsions and upheavals. From 1933 under Adolf Hitler, Germany began to pursue an aggressive policy in Europe. Meanwhile, France in the 1930s was tired, politically divided, and above all dreaded another war, which the French feared would again be fought on their soil for the third time, and again destroy a large percentage of their young men. France's stagnant population meant that it would find it difficult to withhold the sheer force of numbers of a German invasion; it was estimated Germany could put two men of