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
Military history of Luxembourg the predominantly francophone western part of the country was transferred to Belgium. Luxembourg's independence was reaffirmed by the 1839 First Treaty of London and again by the 1867 Second Treaty of London, after the Luxembourg Crisis nearly led to war between Prussia and France. The King of the Netherlands remained Head of State as Grand Duke of Luxembourg, maintaining personal union between the two countries until 1890. At the death of William III, the Dutch throne passed to his daughter Wilhelmina, while Luxembourg (at that time restricted to male heirs by the Nassau Family Pact) passed to Adolph of Nassau-Weilburg.