From 1171 Frederick I proved himself an adherent of the Hohenstaufen party. Specially significant would prove the marriage of Frederick, whose possession lay in the south of the Schwarzwald, with Sofie of Raabs, the heiress of the burgraviate of Nuremberg.
Henceforth, when he was acknowledged in this office by Emperor Henry VI in 1191, he became the founder of both the Swabian branch of the Hohenzollern family and the Franconian line of the (later imperial) House of Hohenzollern, which he called Hohenzollern to distinguish it from the House of Counts of Zollern.
Family and children
With Sofie of Raabs he had following children:
Frederick II of NurembergHeraldry of the Royal Families of Europe, JiříLouda & Michael Maclagan, 1981, pp. 178-179.(d. 30 December 1255). (Swabian branch)