Richard III (2 October 1452 – 22 August 1485) was King of England from 26 June 1483 until his death in 1485. He was the last king of the Plantagenet dynasty and its cadet branch the House of York. His defeat and death at the Battle of Bosworth Field marked the end of the Middle Ages in England.

Richard was created Duke of Gloucester in 1461 after the accession to the throne of his older brother Edward IV. This was during the period known as the Wars of the Roses, an era when two branches of the royal family contested the throne; Edward and Richard were Yorkists, and their side of the family faced off against their Lancastrian cousins. In 1472, Richard married Anne Neville, daughter of Richard Neville, 16th Earl of Warwick, and widow of Edward of Lancaster, son of Henry VI, a Lancastrian. He governed northern England during Edward's reign, and played a role in the invasion of Scotland in 1482. When Edward IV died in April 1483, Richard was named Lord Protector of the realm for Edward's eldest son and successor, the 12-year-old Edward V. Before arrangements were complete for Edward V's coronation, scheduled for 22 June 1483, the marriage of his parents was declared bigamous and therefore invalid. Now officially illegitimate, Edward and his siblings were barred from inheriting the throne. On 25 June, an assembly of lords and commoners endorsed a declaration to this effect, and proclaimed Richard as the rightful king. He was crowned on 6 July 1483. Edward and his younger brother Richard of Shrewsbury, Duke of York, called the "Princes in the Tower", disappeared from the Tower of London around August 1483.

There were two major rebellions against Richard during his reign. In October 1483, an unsuccessful revolt was led by staunch allies of Edward IV and Richard's former ally, Henry Stafford, 2nd Duke of Buckingham. Then, in August 1485, Henry Tudor and his uncle, Jasper Tudor, landed in Wales with a contingent of French troops, and marched through Pembrokeshire, recruiting soldiers. Henry's forces defeated Richard's army near the Leicestershire town of Market Bosworth. Richard was slain, making him the last English king to die in battle. Henry Tudor then ascended the throne as Henry VII.

Richard's corpse was taken to the nearby town of Leicester and buried without ceremony. His original tomb monument is believed to have been removed during the English Reformation, and his remains were wrongly thought to have been thrown into the River Soar. In 2012, an archaeological excavation was commissioned by Ricardian author Philippa Langley with the assistance of the Richard III Society on the site previously occupied by Grey Friars Priory. The University of Leicester identified the human skeleton found at the site as that of Richard III as a result of radiocarbon dating, comparison with contemporary reports of his appearance, identification of trauma sustained at Bosworth and comparison of his mitochondrial DNA with that of two matrilineal descendants of his sister Anne. He was reburied in Leicester Cathedral in 2015.

Richard was born on 2 October 1452, at Fotheringhay Castle in Northamptonshire, the eleventh of the twelve children of Richard, 3rd Duke of York, and Cecily Neville, and the youngest to survive infancy. His childhood coincided with the beginning of what has traditionally been labelled the 'Wars of the Roses', a period of political instability and periodic open civil war in England during the second half of the fifteenth century, between the Yorkists, who supported Richard's father (a potential claimant to the throne of King Henry VI from birth) and opposed the regime of Henry VI and his wife, Margaret of Anjou, and the Lancastrians, who were loyal to the crown. In 1459, his father and the Yorkists were forced to flee England, whereupon Richard and his older brother George were placed in the custody of their aunt Anne Neville, Duchess of Buckingham, and possibly of Cardinal Thomas Bourchier, Archbishop of Canterbury.

When their father and elder brother Edmund, Earl of Rutland, were killed at the Battle of Wakefield on 30 December 1460, Richard and George were sent by their mother to the Low Countries. They returned to England following the defeat of the Lancastrians at the Battle of Towton. They participated in the coronation of their eldest brother as King Edward IV on 28 June 1461, when Richard was named Duke of Gloucester and made both a Knight of the Garter and a Knight of the Bath. Edward appointed him the sole Commissioner of Array for the Western Counties in 1464 when he was 11. By the age of 17, he had an independent command.

Richard spent several years during his childhood at Middleham Castle in Wensleydale, Yorkshire, under the tutelage of his cousin Richard Neville, 16th Earl of Warwick, later known as 'the Kingmaker' because of his role in the Wars of the Roses. Warwick supervised Richard's training as a knight; in the autumn of 1465, Edward IV granted Warwick £1,000 for the expenses of his younger brother's tutelage. With some interruptions, Richard stayed at Middleham either from late 1461 until early 1465, when he was 12 or from 1465 until his coming of age in 1468, when he turned 16. While at Warwick's estate, it is likely that he met both Francis Lovell, who was his firm supporter later in his life, and Warwick's younger daughter, his future wife Anne Neville.

It is possible that even at this early stage Warwick was considering the king's brothers as strategic matches for his daughters, Isabel and Anne: young aristocrats were often sent to be raised in the households of their intended future partners, as had been the case for the young dukes' father, Richard of York. As the relationship between the king and Warwick became strained, Edward IV opposed the match. During Warwick's lifetime, George was the only royal brother to marry one of his daughters, the elder, Isabel, on 12 July 1469, without the king's permission. George joined his father-in-law's revolt against the king, while Richard remained loyal to Edward, even though he was rumoured to have been having an affair with Anne.