Francisco Goya, Charles IV of Spain and His Family (1800–1801). Collection of Museo Nacional del Prado.

Prince Charles and Queen Letizia. Photo: Getty He's a future King and she's a Queen, but Prince Charles and Queen Letizia of Spain greeted each other like dear friends.

Then-Prince Charles, Princess Diana, and Princes William and Harry with the Spanish royal family at the Marivent Palace, August 1987.