Isabella of Portugal (1503 - 1539). Isabella of Portugal was Holy Roman Empress and Queen of Spain, Germany, Italy, Naples and Sicily and Duchess of Burgundy by her marriage to Emperor Charles V. Married to Charles V from 1526 to her death in 1539, she was Queen regent of Spain during the absences of her husband during 1529-1533, 1535-1536 and 1538-1539. Isabella was the granddaughter of the Catholic Monarchs, Isabella I of Castile and Ferdinand II of Aragon. Throughout her life, many compared her to her grandmother for her character and her determination in politics. A woman of great beauty and intelligence, Isabella was undoubtedly the Spanish soul of Charles V who, because of his travels in Europe, spent little time in Spain due to political affairs abroad. It was thanks to the governorships of Empress Isabella that Spain was able to remain independent of imperial policies. Isabella was the second child and eldest daughter of King Manuel I of Portugal and his second wife Maria of Aragon. She was named after her maternal grandmother and her aunt Isabella, who had been her father's first wife. Isabella was second-in-line to the throne until the birth of her brother Luis in 1506. However, as the oldest daughter of Manuel I of Portugal, she was a rather attractive candidate for marriage. Isabella spent a happy childhood in the company of her parents and siblings. She was educated under the supervision of her governess Elvira de Mendoza. She would progressively become a beautiful and intelligent young woman, learning the languages of Latin, Spanish and French, the Christian doctrine and the Renaissance classics. In addition to all this, she was very wealthy, possessing a vast and complete library, composed of works of a spiritual nature, destined for prayer and personal enrichment, as well as more mundane works which were of the Infanta's taste, especially on cavalry. Isabella's mother left in her will, and in a clear message to her husband Manuel, the desire that Isabella should marry only a king or the legitimate son of kings. The ideal candidate for Isabella's husband was her first cousin Charles, the son of Maria's sister Joanna of Castile and Philip the Handsome. A marriage between Charles and Isabella brought a strong alliance between the kingdoms of Spain and Portugal, in accordance with the wishes of their grandparents Isabella and Ferdinand. An alliance between Portugal and Spain was essential in order to continue the exploration of the oceans without incurring clashes with Castile. It is evident that Castile needed Portugal as an ally. In the constant evolution of Europe, now that Charles was sovereign of multiple kingdoms, especially after his election as Holy Roman Emperor, Castile needed allies. It was necessary that Portugal fall under the orbit of Castile and not of France, which had happened in the War of Castilian Succession. To have Portugal as an ally of Castile meant having their backs covered in the Peninsula and overseas, as Portugal was the only naval power that could question the supremacy of Castile in the Atlantic. It was, moreover, the richest kingdom in the Christendom. Portuguese consent had allowed Castile to cement its position in the Canaries and on territories of the Kingdom of Fez and their support was necessary to fight the infidel in Barbary. In conclusion, the alliance with Portugal was a guarantee of peace and stability. However, Charles's Flemish advisors, especially William de Croy, convinced him to relegate the Portuguese alliance to the background and replace it with an alliance with England. In 1521, Charles became engaged to his other first cousin Mary Tudor, daughter of Henry VIII of England and Catherine of Aragon, who was sixteen years younger than Charles and still a child. The engagement between Charles and Mary sought to undo an alliance between England and France, articulated by the ambitious Cardinal Thomas Wolsey. Many in Portugal took the rejection of Isabella as an offence, but Isabella remained determined and hopeful that she would marry Charles. The choice was that she would marry only Charles or she would enter a convent. By 1525, Charles was no longer interested in an alliance with England and could wait no longer for Mary Tudor to get older, as he was determined to have legitimate children. The engagement to Mary Tudor was called off, the alliance with England was abandoned and Charles finally sought to marry Isabella. There were many more advantages in his marrying Isabella-she was closer to Charles in age, she was fluent in Spanish and she offered a handsome dowry of 900,000 Portuguese cruzados or Castilian folds, which was more than enough to solve many of Charles's economic and financial problems brought on by the Italian War of 1521-26.