Magnus, Duke of Holstein (b. 1540)
Magnus of Denmark or Magnus of Holstein (5 September [O.S. 26 August] 1540 – 28 March [O.S. 18 March] 1583) was a Prince of Denmark, Duke of Holstein, and a member of the House of Oldenburg. As a vassal of Tsar Ivan IV of Russia, he was the titular King of Livonia from 1570 to 1578.