William III, Duke of Julich-Berg was a nobleman in the late 16th and early 17th centuries, born in 1560. He was a member of the House of La Marck and ruled over the territories of Jülich and Berg in present-day Germany. His reign was marked by political challenges and conflicts, particularly during the Thirty Years' War. William III was known for his efforts to maintain the independence of his duchies amidst the shifting alliances of European powers. He played a significant role in the regional politics of the time, navigating relationships with neighboring states and managing the complexities of feudal governance.