Charlotte Slottsberg is attributed influence over Duke Charles, and her purported influence exposed her to hostility. She is said to have given him an interest in culture, inspired him to attempt to write plays, and encouraged him to share her interest in champagne, and cheered him up when he was depressed. In 1790, she was rumored to have been given an allowance from king Gustav III of Sweden in exchange for influencing his brother Charles to his advantage, which was commented to in a letter by Charles' sister, princess Sophia Albertina of Sweden on 13 April 1790: "He is truly so blinded and enchanted by that nasty Slottsberg, who makes him do all these stupid things and controls him: she is herself bought by the king, who provides her with a pension and inform her of everything, which he wants the duke to do."