 Starting in May 1628, siege was laid on Stralsund by Albrecht von Wallenstein's troops, commanded by Hans Georg von Arnim.By then, the town with its 20,000 inhabitants was defended by a citizen force of 2,500, a levy of 1,500, and another 1,000 enlisted men.The first major imperial assault on the city took place between 16 and 24 May.