Stephen Bathory
The son of Stephen VIII Báthory and a member of the Báthory family. He was married to Queen Anna Jagiellon and worked closely with Chancellor Jan Zamoyski. During his reign, he focused on consolidating power, defeating rivals like Maximilian II, the Holy Roman Emperor, and quelling rebellions, including the Danzig rebellion. He had a successful reign, especially in military matters. His most significant accomplishment was his victorious campaign against Russia in Livonia, where he defended the Commonwealth's borders and secured a favorable peace treaty called the Peace of Jam Zapolski.