Arthur, Prince of Wales (19/20 September 1486 2 April 1502), was the eldest son of King Henry VII of England and Elizabeth of York. He was Duke of Cornwall from birth, and he was created Prince of Wales and Earl of Chester in 1489. As the heir apparent of his father, Arthur was viewed by contemporaries as the great hope of the newly established House of Tudor. His mother, Elizabeth, was the daughter of Edward IV, and his birth cemented the union between the House of Lancaster and the House of York.

Plans for Arthur's marriage began before his third birthday; he was installed as Prince of Wales two years later. At the age of eleven, he was formally betrothed to Catherine of Aragon, a daughter of the powerful Catholic Monarchs in Spain, in an effort to forge an Anglo-Spanish alliance against France. Arthur was well educated and was in good health for the majority of his life. Soon after his marriage to Catherine in 1501, the couple took up residence at Ludlow Castle in Shropshire, where Arthur died six months later of the sweating sickness, which Catherine survived. Catherine later firmly stated that the marriage had not been consummated.

One year after Arthur's death, Henry VII renewed his efforts to seal a marital alliance with Spain by arranging for Catherine to marry Arthur's younger brother Henry, Prince of Wales, who would ascend to the throne in 1509 as King Henry VIII. The question over whether Arthur and Catherine had consummated their marriage was much later, and in a completely different political context, exploited by Henry VIII and his court. This strategy was employed in order to cast doubt upon the validity of Catherine's union with Henry VIII, eventually leading to the separation between the Church of England and the Roman Catholic Church.

Catherine of Aragon (Spanish: Catalina de Aragón; 16 December 1485 – 7 January 1536) was Queen of England as the first wife of King Henry VIII from their marriage on 11 June 1509 until their annulment on 23 May 1533. She was previously Princess of Wales as the wife of Henry's elder brother, Arthur, Prince of Wales.

The daughter of Isabella I of Castile and Ferdinand II of Aragon, Catherine was three years old when she was betrothed to Prince Arthur, heir apparent to the English throne. They married in 1501, but Arthur died five months later. Catherine held the position of ambassador of the Aragonese crown to England in 1507, the first known female ambassador in European history. She married Arthur's younger brother, the recently ascended Henry VIII, in 1509. For six months in 1513, she served as regent of England while Henry VIII was in France. During that time the English crushed and defeated the Scottish at the Battle of Flodden, an event in which Catherine played an important part with an emotional speech about English courage.By 1525, Henry VIII 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. When Pope Clement VII refused to annul the marriage, Henry defied him by assuming supremacy over religious matters. In 1533 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. Despite this, Henry acknowledged her only as dowager princess of Wales. After being banished from court by Henry, Catherine lived out the remainder of her life at Kimbolton Castle, dying there in January 1536 of cancer. The English people held Catherine in high esteem, and her death set off tremendous mourning. Her daughter Mary would become the first undisputed English queen regnant in 1553.

Catherine commissioned The Education of a Christian Woman by Juan Luis Vives, and Vives dedicated the book, controversial at the time, to the Queen in 1523. Such was Catherine's impression on people that even her enemy Thomas Cromwell said of her, "If not for her sex, she could have defied all the heroes of History." She successfully appealed for the lives of the rebels involved in the Evil May Day, for the sake of their families. Catherine also won widespread admiration by starting an extensive programme for the relief of the poor. She was a patron of Renaissance humanism, and a friend of the great scholars Erasmus of Rotterdam and Thomas More.