Albert Frederick (German: Albrecht Friedrich; Polish: Albrecht Fryderyk; 7 May 1553 – 27 August 1618) was the Duke of Prussia, from 1568 until his death. He was a son of Albert of Prussia and Anna Marie of Brunswick-Lüneburg. He was the second and last Prussian duke of the Ansbach branch of the Hohenzollern family.
George Frederick of Brandenburg-Ansbach (German: Georg Friedrich der Ältere; 5 April 1539 in Ansbach – 25 April 1603) was Margrave of Ansbach and Bayreuth, as well as Regent of Prussia. He was the son of George, Margrave of Brandenburg-Ansbach and a member of the House of Hohenzollern. He married firstly, in 1559, Elisabeth of Brandenburg-Küstrin (29 August 1540 – 8 March 1578). He married secondly, in 1579, Sophie of Brunswick-Lüneburg (30 October 1563 – 1639), daughter of William of Brunswick-Lüneburg and Dorothea of Denmark.
George Frederick reigned in his native Ansbach, Franconia and Jägerndorf, Upper Silesia since 1556 and, after the death of his cousin Albert Alcibiades in 1557, also in Kulmbach. He took over the administration of the Duchy of Prussia in 1577, when the then-reigning Duke Albert Frederick became ill.