William’s pusillanimous attitude (he was actually talking of withdrawing from the country to Nassau) was by no means acceptable to his high-spirited wife.  The princess was all for vigorous action, and she wrung from William a reluctant consent to her returning from Nijmwegen, where for security she had been residing with her family, to the Hague.  In that political centre she would be in close communication with Sir J. Harris and Van de Spiegel, and would be able to organise a powerful opposition in Holland to patriot ascendancy.  It was a bold move, the success of which largely depended on the secrecy with which it was carried out.  On June 28 Wilhelmina started from Nijmwegen, but the commandant of the free corps at Gouda, hearing that horses were being ordered at Schoonhoven and Haasrecht for a considerable party, immediately sent to headquarters for instructions.  He was told not to allow any suspicious body of persons to pass.  He accordingly stopped the princess and detained her at a farm until the arrival at Woerden of the members of the Committee of Defence.  By these Her Highness was treated (on learning her quality) with all respect, but she was informed that she could not proceed without the permit of the Estates of Holland.  The indignant princess did not wait for the permit to arrive, but returned to Nijmwegen.

The British ambassador, Harris, at once brought the action of the Estates of Holland before the States-General and demanded satisfaction; and on July 10 a still more peremptory demand was made by the Prussian ambassador, von Thulemeyer.  Frederick William II was incensed at the treatment his sister had received; and, when the Estates of Holland refused to punish the offending officials, on the ground that no insult had been intended, orders were immediately given for an army of 20,000 men under Charles, Duke of Brunswick, to cross the frontier and exact reparation.  The Prussians entered in three columns and met with little opposition.  Utrecht, where 7000 “patriot” volunteers were encamped, was evacuated, the whole force taking flight and retreating in disorder to Holland.  Gorkum, Dordrecht, Kampen and other towns surrendered without a blow; and on September 17 Brunswick’s troops entered the Hague amidst general rejoicings.  The populace wore Orange favours, and the streets rang with the cry of Oranje boven.  Amsterdam still held out and prepared for defence, hoping for French succour; and thither the leaders of the patriot party had fled, together with the representatives of six cities.  The nobility, the representatives of eight cities, and the council-pensionary remained at the Hague, met as the Estates of Holland, repealed all the anti-Orange edicts, and invited the prince to return.  Amidst scenes of great enthusiasm the stadholder made his entry into the Binnenhof on September 20.  The hopes held by the patriot refugees at Amsterdam of French aid were vain, for the French government was in no position to help anyone.  As soon as the Prussian army appeared before the gates, the Town Council, as in 1650, was unwilling to jeopardise the welfare of the city by armed resistance, and negotiations were opened with Brunswick.  On October 3 Amsterdam capitulated, and the campaign was over.