The male line of the Royal House which ruled in Denmark was dying out; according to a law introduced in 1660, descendants of the female branch might succeed in the Kingdom.

This law had probably never been legally enacted for the Duchies; in Schleswig and Holstein the old Salic law prevailed.

In the ordinary course of things, on the death of Frederick VII., who had succeeded in 1847, the long connection between Holstein and Denmark would cease.

Would, however, Schleswig go with Holstein or with Denmark?
Every Schleswig-Holsteiner and every German declared that the two Duchies must remain for ever "unvertheilt"; the majority of the Danes determined, whatever the law might be, that they would keep Schleswig, which had once been Danish.

The King took a different line; he wished to maintain all the possessions in his House, and that the same man should succeed both in the Kingdom and the Duchies.