Margaret of York in the context of Cecily Neville

The Princes in the Tower refers to the mystery of the fate of the deposed King Edward V of England and his younger brother Prince Richard of Shrewsbury, Duke of York, heirs to the throne of King Edward IV of England. The brothers were the only sons of the king by his queen, Elizabeth Woodville, living at the time of their father's death in 1483. Aged 12 and 9 years old, respectively, they were lodged in the Tower of London by their paternal uncle and England's regent, Richard, Duke of Gloucester, in preparation for Edward V's forthcoming coronation. Before the young king's coronation, however, he and his brother were declared illegitimate by Parliament. Gloucester ascended the throne as Richard III.

It is unclear what happened to the two princes after the last recorded sighting of them in the tower. It is generally assumed that they were murdered; a common hypothesis is that the murder was commissioned by Richard III in an attempt to secure his hold on the throne. Their deaths may have occurred sometime in 1483, but apart from their disappearance, the only evidence is circumstantial. As a result, several other theories about their fates have been proposed, including the suggestion that they were murdered by their kinsman the Duke of Buckingham, their future brother-in-law King Henry VII, or his mother Lady Margaret Beaufort, among others. It has also been suggested that one or both princes may have escaped assassination. In 1487, Lambert Simnel initially was crowned in Dublin as "King Edward", but later claimed by others to be York's cousin the Earl of Warwick. And again several years later, from 1491 until his capture in 1497, Perkin Warbeck claimed to be the Duke of York, having supposedly escaped to Flanders. Warbeck's claim was supported by some contemporaries, including York's aunt the Duchess of Burgundy.

Charles Martin (10 November 1433 – 5 January 1477), called the Bold, was the last duke of Burgundy from the House of Valois-Burgundy, ruling from 1467 to 1477. He was the only surviving legitimate son of Philip the Good and his third wife, Isabella of Portugal. As heir and as ruler, Charles vied for power and influence with rivals such as his overlord, King Louis XI of France. In 1465, Charles led a successful revolt of Louis's vassals in the War of the Public Weal.

After becoming the Duke of Burgundy in 1467, Charles pursued his ambitions for an independent kingdom which would stretch contiguously from the North Sea in the north to the borders of Savoy in the south. For this purpose, he acquired Guelders and Upper Alsace; sought the title King of the Romans; and gradually became an enemy of the Germans. Charles married Margaret of York for an English alliance. He arranged the betrothal of his only child, Mary, to Maximilian of Austria.