Siege of Breda (1637) when word came that the Dutch had suddenly invested the city of Breda with a besieging army of 18,000. Breda was the capital city of the baronial fief that had once been the crown jewel in the Dutch estates of the Nassau family in the Habsburg Netherlands before the war started. Frederick Henry had therefore a personal interest in recapturing the city and its surroundings. The siege was preceded by an attempt to surprise the garrison on 21 July 1637 by Dutch cavalry under Henry Casimir I of Nassau-Dietz. However, the gates were closed in time and the Dutch skirmishers
Congress of Breda fresh congress at Aix-la-Chapelle was arranged, where all warring states would participate, to offer formal approval to the agreement between Britain and France. The peace was formally concluded with the Treaty of Aix-la-Chapelle in 1748 in which all parties participated although the terms had already been agreed in advance by Britain and France at Breda. The terms proved deeply unsatisfactory to Maria Theresa of Austria who was outraged that Austria had lost Silesia and that the British had agreed so at Breda, without any Austrians being present. In the long run, that contributed to the breakdown of the Anglo-Austrian Alliance.