Frederick I, Duke of Brunswick Lüneburg

Frederick (ca. 1357 – 5 June 1400), Duke of Brunswick-Lüneburg, was ruler of the Principality of Brunswick from 1373, and, according to some sources, briefly German king-elect in opposition to Wenceslaus in 1400.

Frederick was the eldest son of Magnus II, Duke of Brunswick-Lüneburg and Catherine of Anhalt-Bernburg.

Frederick was underage until 1381, until which time Otto of Brunswick-Göttingen was his guardian. Like his father, he was thrust into the Lüneburg Succession War, which he and his brothers attempted to end in 1373 by a treaty with the Ascanian dukes of Saxony-Wittenberg. According to this treaty, the rule over the Principality of Lüneburg would alternate between the two families. But the dispute continued; together with his brothers, Frederick eventually won the war by conquering Lüneburg itself in 1388.

In May 1400, Frederick took part in an assembly of the princes of the Holy Roman Empire in Frankfurt; the purpose of the meeting was to discuss the deposition of Wenceslaus, King of the Romans. According to legend, Frederick was elected as an anti-king by a subset of the princes; because no agreement over his election could be reached, he left the assembly. Modern historians are at odds with each other whether Frederick was ever considered a candidate or even elected, since there is no documentary evidence for this. It is undisputed that he was murdered during his journey home by Henry VII, Count of Waldeck and his men, who included Friedrich von Hertingshausen and Konrad von Falkenberg. The murder may have served to get rid of a royal candidate; or the story of the royal election may have sprung up to find a motive for the murder.

The murder caused much concern at the time; a stone cross was erected at its location in Kleinenglis near Fritzlar. Frederick was entombed in Brunswick Cathedral.