The Treaty of London was signed, which recognised and guaranteed the independence and neutrality of Belgium.
In 1813 Napoleon’s rule of the Netherlands was ended by the combined armies of Russia and Prussia, and control was given to William Frederik of Orange-Nassau. Two years later, as a result of the Congress of Vienna, modern Belgium became part of the United Kingdom of the Netherlands.
These southern provinces were predominantly Catholic, and a sizeable number of the inhabitants spoke French. However, William clearly favoured Protestantism and had tried to impose Dutch as the official language. This led to tensions which were exacerbated by economic problems that included high unemployment and arguments over the effect of free trade on the less developed south. A revolution erupted in 1830 that led to the states declaring independence on 4 October, although William refused to recognise the independent Belgium for over nine years.
In signing the treaty that formally recognised the existence of the independent Kingdom of Belgium, the Netherlands were joined by Britain, Austria, France, Russia, and the German Confederation. Furthermore, Britain insisted that the signatories also recognise Belgium’s perpetual neutrality.
The neutrality clause was of central importance in the outbreak of the First World War, since Germany violated Belgium’s neutrality when its forces crossed the border in the Schlieffen Plan. Britain thus claimed to be upholding the Treaty of London when it declared war on 4 August 1914 – much to the anger of German Chancellor Theobald von Bethmann-Hollweg who couldn’t believe Britain would go to war over a ‘mere a scrap of paper’.