His maternal grandparents were King Frederick William II of Prussia and his second wife Frederika Louisa of Hesse-Darmstadt.

He returned to the Netherlands in 1813 when his father became sovereign prince, and in May 1814 succeeded Sir Thomas Graham as the highest-ranking officer of the British forces stationed there.

[16] An inspection into the archives of Siborne by Dutch officer Francois de Bas in 1897 claimed to discover the "selective use of sources" and "numerous miscounts and untruths".

[17] In 1814, William was briefly engaged to Princess Charlotte of Wales, only child of the Prince Regent (later George IV of the United Kingdom) and his estranged wife, Caroline of Brunswick.

[19] William II enjoyed considerable popularity in what is now Belgium (then the Southern Netherlands), as well as in parts of the rest of the Netherlands for his affability and moderation, and in 1830, on the outbreak of the Belgian Revolution, he did his utmost in Brussels as a peace broker, to bring about a settlement based on administrative autonomy for the southern provinces, under the House of Orange-Nassau.

In April 1831, William II was sent by his father to be the military leader during the Ten Days' Campaign in order to recover what would become Belgium.

European mediation established Leopold of Saxe-Coburg-Gotha (widower of William's former fiancée, Charlotte) on the throne of a new monarchy.

On top of that, Williams beloved second son Prince Alexander had fallen ill in January 1847 and the 29-year-old's condition became increasingly concerning as the year continued.

Prince Alexander went to Madeira to winter in a warm climate, but his health only worsened further and his desperate father sent his own personal physician to the island in a last bid attempt to save his son's life.

Warned that the revolution might spread to the Netherlands next, William (who already knew his son had probably died, but still hadn't received an official announcement) decided to institute a more liberal regime, believing it was better to grant reforms instead of having them imposed on him on less favourable terms later.

He chose a committee headed by the prominent liberal Johan Rudolf Thorbecke to create a new constitution, which was instituted on 17 March 1848.

William was absolutely destroyed by grief, lamenting how the entire world was nothing but a large grave that swallowed all glory and honour.

[22] The new document designed by the constitutional committee provided that the Eerste Kamer (Senate), previously appointed by the king, would be elected indirectly by the provincial states.

William appears as a character in the historical fiction novel Sharpe's Waterloo by Bernard Cornwell, and its television adaptation, in which he is portrayed by Paul Bettany.

[33][34][35][36] The homosexual relationships that William II had as crown prince and as king were reported by journalist Eillert Meeter [nl].