No matter how small his defeat, it confirmed that the prince was no longer able to control the country's internal affairs through force. Moreover, a few days later Amsterdam came firmly into Patriot hands when the Orangist Bijltjesoproer was put down on 30 May. His wife Wilhelmina of Prussia's arrest at Goejanverwellesluis (28 June) underlined this powerlessness, and prompted Orange to once more petition Prussia to intervene. King Frederick William II of Prussia mounted diplomatic pressure, but the Patriots were not prepared to make any concessions. In the meantime, the States of Holland formed Defence Commission with the Utrecht Patriots on 19 July on the recommendation of the Amsterdam Patriots. The Prussian invasion of Holland eventually occurred in September 1787, with 25,000 troops easily crushing the Patriot rebels, who did not receive any help from their allies France or the United States, and were forced to surrender within a month. Many Patriots fled to France or the Southern Netherlands, or went underground by forming "reading clubs", that ostensibly convened to discuss books, but actually were about politics. The Orange regime was restored and would survive until the Batavian Revolution of January 1795, supported by Revolutionary France's invading armies with many exiled Patriots amongst their ranks.