Antonio Rincon, also Antoine de Rincon, was a Spanish-born diplomat in the service of France. An influential envoy from the King of France to Sultan Suleiman I of the Ottoman Empire, he made various missions to Constantinople between 1530 and 1541. While an effective diplomat, Rincon's enemies considered him a renegade and some later observers would criticize him for promoting Machiavellian policies.

Sigismund I the Old was King of Poland and Grand Duke of Lithuania from 1506 until his death in 1548. Sigismund I was a member of the Jagiellonian dynasty, the son of Casimir IV and younger brother of Kings John I Albert and Alexander I Jagiellon. He was nicknamed "the Old" in later historiography to distinguish him from his son and successor, Sigismund II Augustus. Before ascending to the Polish and Lithuanian thrones, he was Duke of Głogów from 1499, Duke of Opava from 1501, and governor of Silesia from 1504 on behalf of his brother, King Vladislaus II of Bohemia and Hungary.