The siege of Itzehoe was initiated by Sweden on 6 August, 1657, while chasing the retreating Danish army after the failed campaign in Bremen-Verden.

Charles X Gustav, the king of Sweden, ordered the town to be bombarded into submission, which unintentionally led to massive fires breaking out in the city, forcing the defenders to withdraw on 11 August.

Such bombardments, usually targeted at civilian populations and their houses, had been tested by the Swedes during the Deluge, most recently during a Swedish attack on Brzesc.

[5] The Swedish cannons were put north of Itzehoe, and Erik Dahlbergh was ordered to oversee a heavy 280-pound mortar, which was placed at the bottom of a hill, near a road.

Inbetween the burning houses and smoking ruins, the Swedish cavalry sprung forward, capturing the undefended fortifications in the north and west.

On the same day, 8 August, the Danes retreated from two nearby sconces, Kreuzchanze, situated by Heiligenstedten and the Krummerdeichschanze, which were immediately conquered by the Swedes.