She was Princess of Wales while married to Henry's elder brother, Arthur, Prince of Wales , for a short period before his death. She was three years old when she was betrothed to Arthur, heir apparent to the English throne.
They married in , but Arthur died five months later. Catherine spent years in limbo, and during this time, she held the position of ambassador of the Aragonese crown to England in , the first known female ambassador in European history. For six months in , she served as regent of England while Henry was in France. During that time the English defeated a Scottish invasion at the Battle of Flodden , an event in which Catherine played an important part with an emotional speech about courage and patriotism.
By , Henry was infatuated with Anne Boleyn and dissatisfied that his marriage to Catherine had produced no surviving sons, leaving their daughter Mary as heir presumptive at a time when there was no established precedent for a woman on the throne. He sought to have their marriage annulled, setting in motion a chain of events that led to England's schism with the Catholic Church. In , their marriage was consequently declared invalid and Henry married Anne on the judgement of clergy in England, without reference to the pope.
Catherine refused to accept Henry as supreme head of the Church in England and considered herself the King's rightful wife and queen, attracting much popular sympathy. After being banished from court by Henry, Catherine lived out the remainder of her life at Kimbolton Castle , dying there in January of cancer.
The English people held Catherine in high esteem, and her death set off tremendous mourning. Catherine commissioned The Education of a Christian Woman by Juan Luis Vives , who dedicated the book, controversial at the time, to the Queen in Such was Catherine's impression on people that even her adversary Thomas Cromwell said of her, "If not for her sex, she could have defied all the heroes of History.
