Belgian National Day / Nationale feestdag van België / Fête nationale belge / Belgischer Nationalfeiertag is the national holiday of Belgium commemorated annually on 21 July. It is one of Belgium’s ten public holidays and marks the anniversary of the investiture of King Leopold I, the country’s first monarch, in 1831. In the aftermath of the Napoleonic Wars, Belgium became part of the United Netherlands. Between August and October 1830, the Belgian Revolution forced Dutch forces out of the country. By November, the different revolutionary factions had coalesced around the idea of national independence and began drafting a constitution for the new state. It was decided that it would become a constitutional and popular monarchy. Searching for a monarch, the revolutionaries decided on Prince Leopold of Saxe-Coburg-Gotha, a German aristocrat popular in Great Britain. Leopold arrived in Brussels in July 1831 and, on 21 July, swore allegiance to the constitution, becoming the country’s first monarch. It is thus considered to mark the start of the modern Kingdom of Belgium.