In 1460, Schleswig fell to the Danish royal
House of Oldenburg, in the person of Christian I, who inherited not only the Duchy, a Danish fief, but also the County of Holstein-Rendsburg, a
Saxe-Lauenburgian subfief within the Holy Roman Empire, following the death of his maternal uncle Adolf I (and VIII as Count of Holstein-Rendsburg). In 1474, Lauenburg's
liege lord Emperor
Frederick III elevated Christian as Count of Holstein-Rendsburg to Duke of Holstein, thus becoming an immediate imperial
vassal (see
imperial immediacy). The smaller Holstein-Pinneberg remained a county further ruled by the House of Schauenburg. In 1544, after Christian III's brothers reached majority, they partitioned the Duchies of Holstein (a fief of the Holy Roman Empire) and of Schleswig (a Danish fief) in an unusual way, following negotiations between the brothers and the
Estates of the Realm of the duchies, which opposed a factual partition. They determined their youngest brother
Frederick for a career as Lutheran administrator of an ecclesiastical state within the Holy Roman Empire. So the revenues of the duchies were divided in three equal shares by assigning the revenues of particular areas and
landed estates to each of the elder brothers, while other general revenues, such as taxes from towns and customs dues, were levied together but then shared among the brothers. The estates, whose revenues were assigned to the parties, made Holstein and Schleswig look like patchwork rags, technically inhibiting the emergence of separate new duchies, as intended by the estates of the duchies. The secular rule in the fiscally divided duchies thus became a
condominium of the parties. As dukes of Holstein and Schleswig, the rulers of both houses bore the formal title of "Duke of Schleswig, Holstein,
Dithmarschen and
Stormarn". The dynastic name Holstein-Gottorp comes as convenient usage from the technically more correct
Duke of Schleswig and Holstein at Gottorp. 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. Similar to the above-mentioned agreement Christian III's youngest son
John the Younger gained for him and his heirs a share in Holstein's and Schleswig's revenues in 1564, comprising a third of the royal share, thus a ninth of Holstein and Schleswig as to the fiscal point of view. John
the Younger and his heirs, however, had no share in the condominial rule, they were only titular
partitioned-off dukes. The share of John II
the Elder, who died in 1580, was halved between Adolf and Frederick II, thus increasing again the royal share by a fiscal sixth of Holstein and Schleswig. As an effect the complicated fiscal division of both separate duchies, Holstein and Schleswig, with shares of each party scattered in both duchies, provided them with a condominial government binding both together, partially superseding their legally different affiliation as Holy Roman and Danish fiefs. In 1864, following the
Second Schleswig War, the Duchies of Schleswig and Holstein were ceded by the Danish King and were ruled in a joint condominium by
Austria and
Prussia. Following the defeat of Austria in the
Austro-Prussian War in 1866, they were annexed by Prussia and were formed into the new Prussian
Province of Schleswig-Holstein, part of
Germany since 1870. == Pretenders to Schleswig-Holstein ==