Balthasar Charles, Prince of Asturias (d. 1646)
Balthasar Charles (17 October 1629 – 9 October 1646), Prince of Asturias, Prince of Girona, Duke of Montblanc, Count of Cervera, and Lord of Balaguer, Prince of Viana was heir apparent to all the kingdoms, states and dominions of the Spanish monarchy until his death.