After the collapse of Napoleon in 1813–15, an expanded "United Kingdom of the Netherlands" was created with the House of Orange as monarchs, also ruling Belgium and Luxembourg. The King imposed unpopular Protestant reforms on Belgium, which revolted in 1830 and became independent in 1839. After an initially conservative period, following the introduction of the 1848 constitution, the country became a parliamentary democracy with a constitutional monarch. Modern-day Luxembourg became officially independent from the Netherlands in 1839, but a personal union remained until 1890. Since 1890, it is ruled by another branch of the House of Nassau.