 Adolf, the third son of Duke and King Frederick I and the second youngest half-brother of King Christian III, founded the dynastic branch called House of Holstein-Gottorp, which is a cadet branch of the then royal Danish House of Oldenburg.The Danish monarchs and the Dukes of Holstein-Gottorp listed below ruled both duchies together as to general government, however, collected their revenues in their separate estates.John II "the Elder" conveniently called Duke of Schleswig-Holstein-Haderslev produced no issue, so no branch emerged from his side.