 He was given the task of using his connections in the Caps party to neutralize it and secure the southern provinces by use of the military, tasks he performed successfully and for which the king rewarded him with the title Duke of Södermanland.Duke Charles in early years was the object of his mother's plans to arrange political marriages for her children.On the wish of his mother, he was to be married to her niece, his cousin Philippine of Brandenburg-Schwedt, a plan to which he had agreed in 1770.