Unlike France, the kingdom of Spain had no Salic Law, so it was possible for a female to assume the throne. When Maria Theresa's brother Balthasar Charles, Prince of Asturias, died in 1646, she became heiress presumptive to the vast Spanish Empire and remained such until the birth of Philip Prospero, Prince of Asturias, in 1657. She was heiress presumptive once more between 1 November and 6 November 1661 - the death of Prince Philip and the birth of Prince Charles, who would later inherit the thrones of Spain as Charles II.