In August 1830, stirred by a performance of Auber's La Muette de Portici at the Brussels opera house La Monnaie, the Belgian Revolution broke out, and the country wrested its independence from the Dutch, aided by French intellectuals and French armed forces. The real political forces behind this were the Catholic clergy, which was against the Protestant Dutch king, William I, and the equally strong liberals, who opposed the royal authoritarianism, and the fact that the Belgians were not represented proportionally in the national assemblies. At first, the Revolution was merely a call for greater autonomy, but due to the clumsy responses of the Dutch king to the problem, and his unwillingness to meet the demands of the revolutionaries, the Revolution quickly escalated into a fight for full independence.
The major European powers of the time, (Britain, Russia, Prussia, Austria) were fearful of Belgium either becoming a republic or being annexed to France, and so found a monarch invited in from the House of Saxe-Coburg and Gotha in Germany by the British. On July 21, 1831, the first king of the Belgians, Leopold of Saxe-Coburg was inaugurated. This day is still the Belgian national holiday. Even though the Belgian Revolution violated the accords made in 1815, the Belgians received the sympathy of the liberal governments of both Great Britain and France. France itself had undergone a liberal revolution that year. The other major powers of Europe – Austria and Prussia – took a much dimmer view of Belgian independence but they were disinclined to take any action, being preoccupied with the November Uprising in Poland.