FREDERICK I. (c. 1371-1440), elector of Brandenburg, founder of the greatness of the House of Hohenzollern, was a son of Frederick V., burgrave of Nuremberg, and first came into prominence by saving the life of Sigismund, king of Hungary, at the battle of Nicopolis in 1396. In 1397 he became burgrave of Nuremberg, and after his father's death in 1398 he shared Ansbach, Bayreuth, and the smaller possessions of the family, with his only brother John, but became sole ruler after his brother's death in 1420. Loyal at first to King Wenceslaus, the king's neglect of Germany drove Frederick to take part in his deposition in 1400, and in the election of Rupert III., count palatine of the Rhine, whom he accompanied to Italy in the following year. In 1401 he married Elizabeth, or Elsa, daughter of Frederick, duke of Bavaria-Landshut (d. 1393), and after spending some time in family and other feuds, took service again with King Sigismund in 1409, whom he assisted in his struggle with the Hungarian rebels. The double election to the German throne in 1410 first brought Frederick into relation with Brandenburg. Sigismund, anxious to obtain another vote in the electoral college, appointed Frederick to exercise the Brandenburg vote on his behalf, and it was largely through his efforts that Sigismund was chosen German king. Frederick then passed some time as administrator of Brandenburg, where he restored a certain degree of order, and was formally invested with the electorate and margraviate by Sigismund at Constance on the 18th of April 1417 (see BRANDENBURG). He took part in the war against the Hussites, but became estranged from Sigismund when in 1423 the king invested Frederick of Wettin, margrave of Meissen, with the vacant electoral duchy of Saxe-Wittenberg. In 1427 he sold his rights as burgrave to the town of Nuremberg, and he was a prominent member of the band of electors who sought to impose reforms upon Sigismund. After having been an unsuccessful candidate for the German throne in 1438, Frederick was chosen king of Bohemia in 1440, but declined the proffered honour. He took part in the election of Frederick III. as German king in 1440, and died at Radolzburg on the 21st of September in the same year. In 1902 a bronze statue was erected to his memory at Friesack, and there is also a marble one of the elector in the "Siegesallee" at Berlin. See A. F. Riedel, _Zehn Jahre aus der Geschichte der Ahnherren des preussischen Koenigshauses_ (Berlin, 1851); E. Brandenburg, _Koenig Sigmund und Kurfuerst Friedrich I. von Brandenburg_ (Berlin, 1891); and O. Franklin, _Die deutsche Politik Friedrichs I. Kurfuersten von Brandenburg_ (Berlin, 1851).