During the Kalmar War prince Gustavus Adolphus of Sweden took the town with a small force on June 25, 1611 and destroyed the supplies the Danes had stored there.
Kristianopel's significance as a frontier fortress vanished when Blekinge became Swedish as a consequence of the treaty of Roskilde in 1658 and in 1676 the fortress' equipment was transferred to Karlshamn.