Frederick I, Elector of Saxony (b. 1370)
Frederick I, the Belligerent or the Warlike (German: Friedrich der Streitbare; 11 April 1370 – 4 January 1428), a member of the House of Wettin, ruled as Margrave of Meissen from 1407 and Elector of Saxony (as Frederick I) from 1423 until his death.

He is not to be confused with his cousin Landgrave Frederick IV of Thuringia, the son of Landgrave Balthasar.