Kammala jumla mai zuwa: Poulsen ya sake jagorantar sojojinsa a lokacin barkewar Yakin Dano-Swedish na 1658-1660, kuma ya haɗa kamfaninsa cikin tsaron Copenhagen. An tura Poulsen da kansa zuwa Zealand da aka mamaye don shirya gwagwarmayar yaki. A ranar 22 ga Agusta, 1658, wani doka ya umurci manoman Zealand su taimaka wa Poulsen wajen cin zarafin sojojin mamaye na Sweden. Ya tattara wani kamfani na "snaphane" 'yan bindiga a cikin watan Agusta, kodayake ba shi da goyon baya sosai daga jama'ar yankin. Ya jagoranci hare-haren da yawa da suka yi nasara a kan ƙananan ƙungiyoyin Sweden, amma a ƙarshe an tilasta masa komawa baya. Ya koma Copenhagen, kuma daga baya ya koma rundunar soja. Wataƙila ya kasance wani ɓangare na tsaron birnin a lokacin
An kai hari kan Copenhagen a watan Fabrairun 1659.