Magnus, Duke of Holstein
Magnus of Holstein was a Prince of Denmark and a member of the House of Oldenburg. As a vassal of Ivan IV of Russia, he was the titular King of Livonia from 1570 to 1578.
Duke Magnus was born at the Copenhagen Castle in 1540 as the second son of King Christian III of Denmark and Norway and Dorothea of SaxeLauenburg. At the age ofhe was sent to Germany to be educated at various German courts. Following the death of his father in 1559, he returned to Denmark for the coronation of his older brother, King Frederick II of Denmark.
Source: Wikipedia