In August 1830 Daniel Auber's opera La Muette de Portici, about the repression of Neapolitans, was staged in Brussels. Performances of this show seemed to crystallize a sense of nationalism and "Hollandophobia" in Brussels, and spread to the rest of the South. Rioting ensued, chiefly aimed at the kingdom's unpopular justice minister, Cornelis Felix van Maanen, who lived in Brussels. An infuriated William responded by sending troops to repress the riots. However, the riots had spread to other Southern cities. The riots quickly became popular uprisings. Soon an independent state of Belgium was proclaimed. For several years there was a war between the north and the south but eventually King William I was forced to end the war due to the high costs. The United Kingdom of the Netherlands was dissolved by the Treaty of London (1839) and the northern part continued as the Kingdom of the Netherlands. It was not renamed, however, as the "United"-prefix had never been part of its official name, but rather was retrospectively added by historians for descriptive purposes.
In 1832 Belgium introduced its own series of coins that was also legal tender in Luxembourg. The Dutch guilder coins were no longer in use in Belgium and Luxembourg which had become independent.
