Belgium–Luxembourg Economic Union Belgium–Luxembourg Economic Union The Belgium–Luxembourg Economic Union (, , ), abbreviated to BLEU or UEBL, is an economic union between Belgium and Luxembourg, two countries in the Benelux Union. BLEU was created by a treaty, signed on 25 July 1921, despite a referendum against such a proposal, between Belgium and Luxembourg, and came into effect upon ratification by the Luxembourg Chamber of Deputies on 22 December 1922. Under the terms of the treaty, the economic frontier was lifted and the Belgian franc and Luxembourg franc were set at a fixed parity (though revised in 1935 and 1944) establishing a monetary
Monarchy of the Netherlands old republic as "sovereign prince". In 1815, after Napoleon escaped from Elba, William Frederick raised the Netherlands to the status of a kingdom and proclaimed himself King William I. As part of the rearrangement of Europe at the Congress of Vienna, the House of Orange-Nassau was confirmed as rulers of the Kingdom of the Netherlands, enlarged with what are now Belgium and Luxembourg. At the same time, William became hereditary Grand Duke of Luxembourg in exchange for ceding his family's hereditary lands in Germany to Nassau-Weilburg and Prussia. The Grand Duchy of Luxembourg was a part of the Netherlands (until