Baron Joan Derk van der Capellen tot den Pol, from the Province of Overijssel, was without doubt one of the most important people in the Dutch Patriot Movement. He described himself as a "born regent", but that did not prevent him from being an ardent champion ot the Enlightenment ideals. As a member of the States of Overijssel he applied himself to the abolition of the so-called 'drostendiensten', which compelled the farmers of Overijssel to labour for a pittance a few days every year for the local magistrate, the Drost (bailiff). This relic from medieval times was wrongfully applied in Van der Capellen's opinion. In an address to the States in 1778, he pointed out that these rights had been officially abolished in 1631. He ensured his statement was distributed widely and free of charge among the farmers in the Twenthe region. In the end he won his case but his fellow members in the States excluded him from particpation in their deliberations until 1782.

Previously, he had fallen foul of the Stadholder and the members of the States when he proclaimed himself against expansion of the army and the fleet. When in 1776 the British King asked the Dutch whether he could borrow the Scotch Brigade (a unit of mercenaries in Dutch service) to be deployed in the war with the American Republic, he voted against.

His overt support for the American revolutionaries was not appreciated either. Nevertheless, he continued to dedicate himself to the American War of Independence. He regarded the American struggle as an example for Dutch Patriots. To lend support to his views he translated Observations on civil liberty by the American Richard Price into Dutch. The book was an important inspiration to the American revolutionaries. The Dutch translation was banned in 1789, together with other patriot writings.

In 1780 Van der Capellen arranged a loan for the American cause. Eventually an amount of two hundred thousand guilders was raised. He contributed twenty thousand guilders himself.

The year 1781 was to be the most important in his political career. In that year a pamphlet appeared entitled "Aan het Volk van Nederland" ("To the People of the Netherlands"). In this anonymous pamphlet the disadvantages of the hereditary stadholderate were explained. It should be replaced by a democratic society, based on popular sovereignty. Within a month after publication the pamphlet was banned. Besides, a substantial reward was offered to whoever would report the author. In spite of these measures it was illegally reprinted and distributed three times, and even translated into French, English and German. It was to exert a lasting influence on the democratic movement in the Netherlands.

Van der Capellen, the author of the pamphlet, was forced to enjoy its success in silence, as well as the fact that the authorities failed to identify him as the author. With unflagging zeal he continued to propagate the American cause. Partly thanks to his influence, John Adams and with him the young American Republic were recognized in 1782 by the States General.

He died in 1784. Even after his death he continued to rouse the emotions. A few years after he died his monument was blown up by Orangists.