In 1632 troops of the legitimate ruler of the Prince-Archbishopric, Administrator John Frederick, helped by troops from Sweden and the city of Bremen, reconquered the Prince-Archbishopric. The convent was dissolved. By the Peace of Westphalia the Prince-Archbishopric was transformed into the Duchy of Bremen in 1648, which - together with the Principality of Verden - was first given as a prey for its participation in the Thirty Years' War to be ruled in personal union by the Swedish Crown. These two imperial fiefs to the Swedes are thus colloquially called Bremen-Verden. The queen regnant Christina of Sweden, in personal union Duchess of Bremen and Princess of Verden installed in the two latter functions her residence in today's "Queen Christina House" in Zeven, the oldest remaining profane building in town.