This king to which Marcin Kromer was a personal secretary was also a grand duke of what country?
Marcin Kromer Marcin Kromer (Latin: "Martinus Cromerus"; 11 November 1512 – 23 March 1589) was Prince-Bishop of Warmia (Ermland), a Polish cartographer, diplomat and historian in the Kingdom of Poland and later in the Polish-Lithuanian Commonwealth. He was a personal secretary to two Kings of Poland, Sigismund I the Old and Sigismund II Augustus.
Louis II, Elector of Brandenburg Louis the Roman (German: "Ludwig VI der Römer" ) (7 May 1328 – 17 May 1365) was the eldest son of Emperor Louis IV the Bavarian by his second wife, Margaret II, Countess of Hainault, and a member of the House of Wittelsbach. Louis was Duke of Bavaria as Louis VI (1347–1365) and Margrave of Brandenburg (1351–1365) as Louis II. As of 1356, he also served as Prince-elector of Brandenburg.