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.