The antagonism between the two houses started with the overthrow of King Richard II by his cousin, Henry Bolingbroke, Duke of Lancaster, in 1399. With the support of most of the nobles, Bolingbroke then deposed Richard and was crowned as Henry IV. As an issue of Edward III's third son John of Gaunt, Bolingbroke had a comparatively poor claim to the throne. Roger Mortimer had died the previous year however, and no nobles immediately championed his young son Edmund's claim to the crown. Henry IV died in 1413. His son and successor, Henry V, inherited a temporarily pacified nation. There was one conspiracy against Henry during his short reign; the Southampton Plot led by Richard, Earl of Cambridge, a son of Edmund of Langley, the fourth son of Edward III. Cambridge's wife, Anne Mortimer, also had a claim to the throne, being the daughter of Roger Mortimer and thus a descendant of Lionel of Antwerp. Her brother Edmund, who loyally supported Henry, died childless, and his claim therefore passed to Anne.
Richard, the son of Cambridge and Anne Mortimer, was four years old at the time of his father's execution. The title of Duke of York descended to him from Cambridge's elder brother, Edward of Norwich, 2nd Duke of York, who died fighting alongside Henry at Agincourt. Although Cambridge was attainted, Henry later allowed Richard to inherit the title and lands of his late uncle, who died without issue.
