The foreign policy of the Netherlands is based on four basic commitments: to the Atlantic cooperation, to European integration, to international development and to international law. While historically the Kingdom of the Netherlands was a neutral state, since 1945 it has become a member of NATO, the United Nations, the European Union and many other international organizations. The Dutch economy is very open and relies on international trade. During and after the 17th century—its Golden Age—the Dutch built up a commercial and colonial empire. It was a leading shipping and naval power and was often at war with England, its main rival. Its main colonial holding was Indonesia, which fought for and achieved independence after 1945. The historical ties inherited from its colonial past still infl