Premiere of the 23/24 season at the Teatro La Scala of Milan, broadcast live. The story of Verdi's opera is based on conflicts in the life of Carlos, Prince of Asturias (1545–1568). Though he was betrothed to Elisabeth of Valois, part of the peace treaty ending the Italian War of 1551–59 between the Houses of Habsburg and Valois demanded that she be married instead to his father Philip II of Spain.