Adelaide of Cleves was a German noblewoman born around 1455. She was the daughter of John III, Duke of Cleves and Mathilde of Bavaria. In 1474, she married William IV, Duke of Bavaria, strengthening the political ties between their families. Adelaide played a significant role in the governance of her husband's duchy. Adelaide's marriage produced several children, including Louis X of Bavaria. After William's death in 1508, she became a widow and took on a more prominent role in the affairs of the duchy. She passed away in 1518, leaving a legacy as a key figure in the House of Cleves.