Duke Christian August of Schleswig-Holstein was a German nobleman born in 1622. He was a member of the House of Oldenburg and served as the Duke of Schleswig and Holstein from 1654 until his death in 1659. His reign was marked by efforts to strengthen the duchy and improve its administration. Christian August was also known for his military involvement during the Thirty Years' War, which significantly impacted the region. He was a supporter of the Danish Crown and worked to maintain stability in Schleswig-Holstein during a tumultuous period in European history.