This is the famous Queen of the Netherlands who served as constitutional monarch from 1898 until she resigned in 1948 in favor of her daughter Juliana. During this time, she was keenly interested in the armed services, dispatched a gunboat to South Africa during the Boer Wars, and rendered invaluable service by heading the exile government during the Nazi occupation, sacking a timid politician in the process. She died in 1962. Her Wikipedia article is here.