Prince Carlos Hugo, Hereditary Duke of Parma

Carlos Hugo, Duke of Parma and Piacenza was the head of the ducal House of Bourbon-Parma from 1977 until his death. Carlos Hugo was a Carlist claimant to the throne of Spain and sought to change the political direction of the Carlist movement through the Carlist Party, of which he was the official head during the fatal Montejurra incidents. His marriage to Princess Irene of the Netherlands in 1964 caused a constitutional crisis in the Netherlands.