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
Breda had a population of in ; the metropolitan area had a population of . It is part of the Brabantse Stedenrij. In the 11th century, Breda was a direct fief of the Holy Roman Emperor, its earliest known lord being Henry of Brunesheim (1080–1125). The city of Breda obtained a municipal charter in 1252. After that Breda had the rights to build fortifications. The city constructed brick walls and Roman-style gates. In 1327, Adelheid of Gaveren sold Breda to Duke Johannes III of Brabant. In 1350, the fief was resold to Johannes II of Wassenaar (d. 1377). In 1403, the