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Sophie, who was brought up as a Protestant, married the future Elector John George of Brandenburg on 15 February 1545. She died before he acceded to the Electorate and never reigned as Electress of Brandenburg. Her son (and only child) Joachim Frederick did, however, accede to the Electorate in 1598.
References
Daniel Martin Ernst Kirchner: The princesses and queens on the throne of the Hohenzollerns, 2nd Part: The last eight princesses, Berlin, 1867, p. 1-4.