Joachim Ernst, Duke of Schleswig was a German nobleman born in 1580. He was a member of the House of Schleswig-Holstein and served as the Duke of Schleswig from 1622 until his death in 1624. His reign was marked by the challenges of the Thirty Years' War, which affected many regions in Europe. During his short rule, Joachim Ernst focused on maintaining stability in his duchy. He was known for his efforts to manage local affairs and support his subjects during a tumultuous period. His legacy is tied to the broader history of the Duchy of Schleswig and its role in European conflicts.