Duke of Urach
Because of a lack of male heirs under Salic law, on the death of Wilhelm II in 1921 the royal house had to reach back to the descendants of Friedrich II Eugen (ruled 1795–97). The line of the Duke of Urach was excluded because of a morganatic marriage back in 1800 by its forebear Duke William, and so the succession devolved to the younger branch of Altshausen.