The question, which had already come to the fore in 1848, boiled up again in 1863, when King Frederik VII of Denmark died without an heir. Since the rules allowed succession through the female line in Denmark but not, because of the Salic Law, in the German Confederation, to which the duchies belonged, the new king, Christian IX, who did indeed inherit through the female line, could not become Duke of Schleswig and Holstein, which would have to come under a relative who inherited through the male line.
