Catherine of Aragon was the Queen of England from June 1509 until May 1533 as the first wife of King Henry VIII; she was previously Princess of Wales as the wife of his elder brother Arthur.
Joanna of Castile , called the Mad (Spanish: Juana la Loca), was queen of Castile from 1504 and of Aragon from 1516. From the union of these two crowns modern Spain evolved. Joanna married Philip the Handsome on October 20, 1496. Philip was crowned King of Castile in 1506, initiating the rule of the Habsburgs in Spain. After Philip's death that same year, Joanna was deemed mentally ill and was confined to a nunnery for the rest of her life. Though she remained the legal queen of Castile throughout this time, her father, Ferdinand II of Aragon, was regent until his death, when she inherited his kingdom as well. From 1517, her son, Charles, ruled as king, while she nominally remained co-monarch.
Catherine of Austria was Queen of Portugal as wife of King John III, and regent during the minority of her grandson, King Sebastian, from 1557 until 1562.
Eleanor of Austria was born an Archduchess of Austria and Infanta of Castile from the House of Habsburg.
Mary of Austria was queen consort of Hungary and Bohemia as the wife of King Louis II, and was later Governor of the Habsburg Netherlands.
Ferdinand I was Holy Roman Emperor from 1558, king of Bohemia and Hungary from 1526, and king of Croatia from 1527 until his death. Before his accession, he ruled the Austrian hereditary lands of the Habsburgs in the name of his elder brother, Charles V, Holy Roman Emperor. Also, he often served as Charles' representative in Germany and developed useful relationships with German princes.
Isabella of Austria Archduchess of Austria and Infanta of Castile and Aragon,
Charles V, or Charles I (was a Duke of Burgundy and Holy Roman Emperor. He was ruler of both the Spanish Empire from 1516 and the Holy Roman Empire from 1519, as well as of Habsburg Netherlands from 1506. He voluntarily stepped down from these and other positions by a series of abdications between 1554 and 1556. Through inheritance, he brought together under his rule extensive territories in western, central, and southern Europe, and the Spanish colonies in the Americas and Asia. As a result, his domains spanned nearly four million square kilometers and were the first to be described as "the empire on which the sun never sets"