Wars of the Roses: The Yorkists defeated the Lancastrian army at the Battle of Towton, allowing Edward IV to secure the English throne.

The Wars of the Roses, known at the time and in following centuries as the Civil Wars, and also the Cousins' War, were a series of armed confrontations, machinations, battles and campaigns fought over control of the English throne from 1455 to 1487. The conflict was fought between supporters of the House of Lancaster and House of York, two rival cadet branches of the royal House of Plantagenet. The conflict resulted in the end of Lancaster's male line in 1471, leaving the Tudor family to inherit their claim to the throne through the female line. Conflict was largely brought to an end upon the union of the two houses through marriage, creating the Tudor dynasty that would subsequently rule England.

The House of York was a cadet branch of the English royal House of Plantagenet. Three of its members became kings of England in the late 15th century. The House of York descended in the male line from Edmund of Langley, 1st Duke of York, the fourth surviving son of Edward III. In time, it also represented Edward III's senior line, when an heir of York married the heiress-descendant of Lionel, Duke of Clarence, Edward III's second surviving son. It is based on these descents that they claimed the English crown. Compared with its rival, the House of Lancaster, it had a superior claim to the throne of England according to cognatic primogeniture, but an inferior claim according to agnatic primogeniture. The reign of this dynasty ended with the death of Richard III of England at the Battle of Bosworth Field in 1485. It became extinct in the male line with the death of Edward Plantagenet, 17th Earl of Warwick, in 1499.

The House of Lancaster was a cadet branch of the royal House of Plantagenet. The first house was created when King Henry III of England created the Earldom of Lancaster—from which the house was named—for his second son Edmund Crouchback in 1267. Edmund had already been created Earl of Leicester in 1265 and was granted the lands and privileges of Simon de Montfort, 6th Earl of Leicester, after de Montfort's death and attainder at the end of the Second Barons' War. When Edmund's son Thomas, 2nd Earl of Lancaster, inherited his father-in-law's estates and title of Earl of Lincoln he became at a stroke the most powerful nobleman in England, with lands throughout the kingdom and the ability to raise vast private armies to wield power at national and local levels. This brought him—and Henry, his younger brother—into conflict with their cousin King Edward II, leading to Thomas's execution. Henry inherited Thomas's titles and he and his son, who was also called Henry, gave loyal service to Edward's son King Edward III.