Isabella of Portugal

Born 24 October 1503, Isabella was Portuguese by birth and empress by marriage. When she wed Charles V on 10 March 1526, she became Queen of Spain and Germany, and later Holy Roman Empress in February 1530, holding more titles than most rulers ever see. But the real weight came when Charles left to manage his vast domains: she acted as regent, governing Spain in his long absences, making the decisions that kept the kingdom running while he moved across continents. She died 1 May 1539, thirty-five years old, having spent more time running Spain than many monarchs get in a full reign.