The famous Napoleon was the one who turned the Netherlands into the Dutch Kingdom (under his rule) in the beginning of the 19th Century. When the Netherlands became one of the first to declare the Independence of America, Britain didn’t delay in declaring war. Unfortunately, the Anglo-Dutch War was long and disastrous for the Netherlands. Its economy and other layers of the state were deeply shaken. Some people quickly announced the war as the death toll of Dutch splendour and dominance. At least 40,000 people (which is a huge number for that historical era) migrated to the Country of Brabant.

The French occupation of the Netherlands ended with the death of Napoleon. William VI of Orange played an important role in the whole process of liberation. The Kingdom of the United Netherlands was created, and William VI of Orange became its sovereign in 1813. He was not a successful monarch, because he signed a contract with the British which gave 'on loan' some of its colonial possessions. The condition became permanent for some of them, like Ceylon, which was never given back to the Netherlands. Many other lands, like Indonesia for example, were the object of many treaties between the Dutch and British authorities.

When the Napoleonic era ended, the Netherlands rejoiced because they were put back on the map of Europe. In particular, the Russian tsar supported the Netherlands and insisted that the colonies be given back..
 
A compromise was reached with Great Britain at the Vienna Congress, but only the Dutch East Indies were given back. Also, an extraordinary event took place – the Netherlands became united with two capitals, Amsterdam and Brussels. This was a precedent, and happened in 1815. After that, however, the French-speaking part became dominant and the Netherlands started feeling like second-class citizens in their own state. The people were also divided in terms of religious principles – predominantly Roman Catholic in the south and Protestant in the north. The economic conditions were also different – the south just beginning to industrialize, whereas the north had always been a merchant’s nation. In 1830, the tension escalated and the Belgian people declared war on their northern co-citizens; the French army was mobilized, and the north refused to acknowledge the state of Belgium.

In 1848, insecurity and tension broke out all around Europe. Even though there were no major current affairs in the Netherlands, the foreign developments made King William II reconcile with what his people wanted – to agree to democratic, liberal reformation of the state. That same year, the constitution was rewritten and this turned the Netherlands into a constitutional monarchy. The country was liberalized as early as the middle of the 19th Century. In that aspect, it was one of leading countries in the Old World, if not the most advanced. The link between monarch, government and parliament has stayed unchanged, with very little deviation, ever since. The union between the Netherlands and Luxemburg came to an end in the last years of the 19th Century, when the last male duke died, as the rules for ascendancy didn’t allow a woman to become a ruling Grand Duchess.

By the beginning of the 20th Century, the Netherlands had strengthened their hold on Indonesia, which proved to be their most important colony (though others like Sri Lanka and Brazil were also significant).