Philip the Handsome

Son of Maximilian I and Mary of Burgundy, married to Joanna of Castile in the dynastic match that yoked Spain to the Habsburg patrimony. His brief reign as king of Castile, jointly with his wife, was cut short when he died at twenty-eight, leaving the inheritance to his six-year-old son Charles. He never sat on the Austrian or imperial throne, but every European Habsburg monarch after him descends through his line.