Philip IV was married twice. His first wife was Elizabeth (Isabel) of Bourbon (1602 -1644), princess of France, daughter of King Henry IV of France and Marie de Medici; she married Philip IV in 1615 before he came to the throne. Her betrothal was depicted by Rubens in The Exchange of Princesses. Their 1st child, daughter Maria Theresa (1638-83), was the first wife of Louis XIV of France. His second wife was his own niece, Marianna of Austria, daughter of Philip IVs sister, Maria Anna and Ferdinand III.
Philip IV was succeeded by his four-year-old son, Charles II, the last of the Habsburgs.
See: Diego Velázquez. Philip IV in Armour. Portrait of Phillip IV. Philip IV in Brown and Silver. Queen Isabel, Standing. Queen Margarita on Horseback. Philip IV on Horseback. Infanta Maria Teresa. Queen Mariana. Portrait of Phillip IV.
Prince Baltasar Carlos, Prince of Asturias (1629 1646) son
of Philip IV and Elizabeth (Isabel).
See: Diego Velázquez. Prince Baltasar Carlos with a Dwarf. Prince Baltasar Carlos on Horseback. Prince Baltasar Carlos as a Hunter. Prince Baltasar Carlos with the Count-Duke of Olivares at the Royal Mews.
Prince Felipe Próspero (1657-1661) son of King Philip
IV of Spain and Maria Anna of Austria.
See: Diego Velázquez. Prince Felipe Próspero.
Infanta Margarita or Margaretha Maria of Austria (1649/51-1673)
daughter of King Philip IV and Maria Anna of Austria. (Different sources
give different dates of her life)
See: Diego Velázquez. Infanta Margarita. Infanta Margarita. Infanta Margarita. Infanta Margarita in a Blue Dress.