Start of the Wars of the Roses: At the First Battle of St Albans, Richard, Duke of York, defeats and captures King Henry VI of England.

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 First Battle of St Albans took place on 22 May, 1455, at St Albans, 22 miles (35 km) north of London, and traditionally marks the beginning of the Wars of the Roses in England. Richard, Duke of York, and his allies, the Neville Earls of Salisbury and Warwick, defeated a royal army commanded by Edmund Beaufort, Duke of Somerset. Unusually, the battle was contested in the town of St Albans itself, with the bulk of the fighting taking place in the streets and a tavern being used as a redoubt. Somerset was killed in the battle, and King Henry VI captured, clearing the way for a subsequent parliament to appoint Richard of York Lord Protector.

Richard of York, 3rd Duke of York, also named Richard Plantagenet, was a leading English magnate and claimant to the throne during the Wars of the Roses. He was a member of the ruling House of Plantagenet by virtue of being a direct male-line descendant of Edmund of Langley, King Edward III's fourth surviving son. However, it was through his mother, Anne Mortimer, a descendant of Edward III's second surviving son, Lionel of Antwerp, that Richard inherited his strongest claim to the throne, as the opposing House of Lancaster was descended from John of Gaunt, Duke of Lancaster, the third surviving son of Edward III. He also inherited vast estates and served in various offices of state in Ireland, France and England, a country he ultimately governed as Lord Protector due to the mental instability of King Henry VI.