Hans or Johann I (1406-64), nicknamed "the Alchemist", was a Margrave of Brandenburg and the head of the House of Hohenzollern 1440-57.

He was the eldest son of Frederick I, Elector of Brandenburg (1371-1440), the first Hohenzollern to have Brandenburg (1412-40), and his wife Elisabeth of Bavaria, daughter of Frederick II of Bavaria, Duke of Landshut, and his second wife Magdalena Visconti of Milan.

In 1425, the constant feuds and disorders in Brandenburg have annoyed his father to the end of his tolerance, so that he withdrew to his castle at Cadolz and transferred the regency of the margravate to Hans. Frederick, however, remained elector. Hans did not like the local Brandenburger nobility better either.

His father divided the inheritance in a way that his favored, and iron-willed, second son, Frederick II, received the Brandenburg fief, the family's new land in north. Hans renounced from it. Frederick II continued the efforts to subjugate local nobility, which task he seems to have been suited for. Hans however did not renounce the margravial title of Brandenburg, but had only nominal position to that big fief, and the titukr headship of the house. He did not act as Elector during his tenure, as there were no election in that time - so, the question who had been the prince-elector did not arise. Instead he had the Franconian lands as his portion, Bayreuth (and Nuremberg) as his main seats.

He married Barbara of Saxony (1406-65) and had three surviving daughters (his only legitimate son died under one year):

• Barbara (1423-81) who married Louis III, Marquess of Mantua

• Elisabeth (1425-65) who married first Joachim, Duke of Pomerania and second Vratislas X, Duke of Pomerania

• Dorothea (1430-95) who became queen of Denmark, Norway and Sweden (in her both marriages), marrying first king Christopher III of Denmark, Norway and Sweden, and second king Christian I of Denmark etc.

His next brother Frederick II, Elector of Brandenburg, survived him. House of Hohenzollern | Margraves of Brandenburg-Ansbach | Margraves of Bayreuth | 1406 births | 1464 deaths