Luxembourg an independent state under the personal possession of William I of the Netherlands with a Prussian garrison to guard the city against another invasion from France. In 1839, following the turmoil of the Belgian Revolution, the purely Oil-speaking part of Luxembourg was ceded to Belgium and the Luxembourgish-speaking part (except the Arelerland, the area around Arlon) became what is the present state of Luxembourg. Luxembourg is a founding member of the European Union, OECD, United Nations, NATO, and Benelux. The city of Luxembourg, which is the country's capital and largest city, is the seat of several institutions and agencies of
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