Catherine first married to Prince Arthur, the eldest son of Henry VII of England, in 1501. As Prince of Wales, Arthur was sent to Ludlow Castle on the borders of Wales, to preside over the Council of Wales, and Catherine accompanied him. A few months later, they both became ill, possibly with the sweating sickness which was sweeping the area. Catherine herself nearly died; she recovered to find herself a widow. Catherine testified that, because of the couple's youth, the marriage had not been consummated; Pope Julius II then issued a dispensation, so that Catherine could become betrothed to Arthur's younger brother, the future Henry VIII of England. Catherine of Aragon was said to have made the road 'Aragon Road' in the village of Great Leighs, Chelmsford, and was said to have lived in the Windsor house on that road.
The marriage did not take place until after Henry VIII ascended the throne in 1509, the marriage on June 11, followed by the coronation on June 24, 1509. Both as Princess of Wales and as Queen, Catherine was extremely popular with the people. She governed the nation as Regent while Henry invaded France in 1513.
Henry VIII supposedly married Catherine of Aragon at his father's dying wish and was happily-enough married to her, although not faithful, for 18 years, until he became seriously worried about getting a male heir to his throne as she approached menopause. Her first child, a daughter, was stillborn in 1510. Prince Henry, Duke of Cornwall was born in 1511 but died after 52 days. Catherine then had a miscarriage, followed by another short-lived son. On February 18, 1516 at the Palace of Placentia in Greenwich, London, she gave birth to a daughter named Mary (later Queen Mary I of England). There was another miscarriage in 1518. A male heir was essential to Henry. The Tudor dynasty was new, and its legitimacy might still be tested. The last time a female had inherited the English throne civil war had occurred; Henry I of England's daughter Empress Matilda had been ousted from the throne immediately upon succeeding as the English Barons refused to allow a woman to rule. The disasters of civil war were still fresh in living memory from the Wars of the Roses (1455 – 1485).
In 1520, Catherine's nephew Charles V paid a state visit to England, and the Queen urged the policy of gaining his alliance rather than that of France. Immediately after his departure, May 31, 1520, she accompanied the king to France on the celebrated visit to Francis I, remembered (from the splendors of the occasion) as the Field of the Cloth of Gold. Within two years, however, war was declared against France and the Emperor once again made welcome in England, where plans were afoot to betroth him to Henry and Catherine's daughter Princess Mary.
At this point Catherine was not in physical condition to undergo further pregnancies. The marriage was further soured by trouble made by Catherine's father, Ferdinand, over payments of her dowry and by a shift of allegiance on the part of Ferdinand, who signed a treaty with the French, to Henry's fury. Because of the lack of heirs, Henry began to believe that his marriage was cursed and sought confirmation from two verses of the biblical Book of Leviticus, which said that, if a man marries his brother's wife, the couple will be childless. He chose to believe that Catherine had lied when she said her marriage to Arthur had not been consummated, therefore making their marriage wrong in the eyes of God. He therefore asked Pope Clement VII to annul his marriage in 1527.Catherine died of a form of cancer at Kimbolton Castle, on January 7, 1536 and was buried in Peterborough Cathedral with the ceremony due to a Princess Dowager of Wales, not a Queen. Catherine's embalmer confessed to her doctor that Catherine's heart had been black through and through, which led many people to believe that Anne Boleyn had poisoned her. Henry did not attend the funeral, nor did he allow Princess Mary to do so.
The Pope stalled on the issue for seven years without making a final judgement, partially because allowing an annulment would be admitting that the Church had been in error for allowing a special dispensation for marriage in the first place, and partially because he was a virtual prisoner of Catherine's nephew Charles V, who had conquered Rome. Henry separated from Catherine in July 1531, and married one of Catherine's former ladies-in-waiting (and sister of his former mistress Lady Mary Boleyn), Anne Boleyn in January 1533. Henry finally had Thomas Cranmer, archbishop of Canterbury, annul the marriage himself on May 23, 1533. To forestall an appeal to Rome, which Catherine would have almost certainly won, he had Parliament pass the Act of Supremacy, repudiating Papal jurisdiction in England, making the king the head of the English church, and beginning the English Reformation.
Catherine refused to acknowledge the divorce and took the issue to the law, but she lost and was forced to leave Court. She was separated from her daughter (who was declared illegitimate) and was sent to live in remote castles and in humble conditions, in the hope that she would surrender to the inevitable; but she never accepted the divorce and signed her last letter, "Katherine the Queen." By this time, she was aware that Henry's marriage to Anne was turning bad, and she had not ceased to hope that he might one day return to her.