Frederick of Altmark
Margrave of Brandenburg, Lord of the Altmark
Frederick III of Brandenburg, nicknamed the Fat, also the Younger (born: c. 1424; died: 6 October 1463 in Tangermünde) was Margrave of Brandenburg and Lord of the Altmark.
Life
Frederick was the youngest son of the Elector Frederick I of Brandenburg (1371–1440) from his marriage to Elizabeth (1383–1442 ), daughter of the Duke Frederick of Bavaria-Landshut.
His father's testament, stipulated that Frederick should rule the Margraviate of Brandenburg jointly with his older brother Frederick Irontooth, who also acted as his guardian from 1440 onwards, until at least 1456. Frederick III, however, began urging for more independence in 1445. He was supported by his brothers John and Albert Achilles. In 1447, Frederick received his own territory, consisting of the Altmark and Prignitz, under the sovereignty of Electoral Brandenburg. He fostered the influx of Jews into his territory, after his brother had driven them out of his margraviate in 1446. Frederick III resided in Tangermünde, Salzwedel and Arneburg. He neglected the business of government in such a way that his brother found it necessary in 1459 to intervene militarily against the intrigues in the country.
Since Frederick died without male heirs, the Altmark and Priegnitz fell back to the Electorate of Brandenburg when he died in 1463.
Begin with the source’s own compact description: “Frederick of Altmark” is margrave of Brandenburg, Lord of the Altmark. The dossier treats that line as a proposition to test through Frederick, Altmark and Margrave, not as a finished interpretation.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Jun 7, 2026. The linked authority identifier is Q325948. VIAF identifies the subject as 80584644. 2 of 2 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1424, 1463, 1371 and 1440.
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This entry incorporates text from “Frederick of Altmark” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.