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
Grand Ducal Gendarmerie (Luxembourg) Belgium on the model of the French Gendarmerie, was extended to Luxembourg. After the Belgian Revolution in October 1830, Luxembourg was divided into two parts: the larger part formed the Belgian Province de Luxembourg; the other became the present-day Grand Duchy of Luxembourg, still ruled by the Netherlands. Until 1839, it was controlled by the Dutch Constabulary. Luxembourg was made an independent state (still ruled by the Dutch King in personal union) by the Treaty of London of 19 April, and the creation of a local police force was necessary. The Ordinance of 29 January 1840 created the "Grand Duchy