He was a son of
Louis III, Elector Palatine and his second wife
Matilda of Savoy. His maternal grandparents were
Amadeus, Prince of Achaea and his wife Catherina of Geneva. He ruled the
Electoral Palatinate after the death of his brother
Louis IV as regent for his nephew
Philip, Elector Palatine. He adopted his nephew in 1451 and refused to marry. From this "Arrogation", he claimed the right to be the legitimate elector. As this action was against imperial law, Emperor
Frederick III refused to confirm Frederick's status. However, the emperor did not manage to displace Frederick who was an able strategist and allied with
Louis IX, Duke of Bavaria. Frederick was also successful against other opponents such as the emperor's party follower
Albrecht III Achilles, Elector of Brandenburg and
Diether von Isenburg, the
archbishop of Mainz, and increased his territory. With the
Battle of Seckenheim during the
Bavarian War (1459–1463) Frederick captured his antagonists Bishop
George of Baden,
Charles I, Margrave of Baden-Baden and
Ulrich V, Count of Württemberg. ==Marriage and children==