Richard Neville, 16th Earl of Warwick, defeats the king's Lancastrian forces and takes King Henry VI prisoner in the Battle of Northampton.

Richard Neville, 16th Earl of Warwick, 6th Earl of Salisbury,, known as Warwick the Kingmaker, was an English nobleman, administrator, landowner of the House of Neville fortune and military commander. The eldest son of Richard Neville, 5th Earl of Salisbury, he became Earl of Warwick through marriage, and was the wealthiest and most powerful English peer of his age, with political connections that went beyond the country's borders. One of the leaders in the Wars of the Roses, originally on the Yorkist side but later switching to the Lancastrian side, he was instrumental in the deposition of two kings, which led to his epithet of "Kingmaker".

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.

Henry VI was King of England from 1422 to 1461 and 1470 to 1471, and disputed King of France from 1422 to 1453. The only child of Henry V, he succeeded to the English throne at the age of eight months, upon his father's death, and to the French throne on the death of his maternal grandfather, Charles VI, shortly afterwards.