The accession of Henry IV sowed the seeds for a period of unrest which ultimately broke out in civil war. Fraught by rebellion and instability after his usurpation of Richard II, Henry IV found it difficult to enforce his rule. His son, Henry V, fared better, defeating France in the famous Battle of Agincourt (1415) and staking a powerful claim to the French throne. Success was short-lived with his early death.

By the reign of the relatively weak Henry VI, civil war broke out between rival claimants to the throne, dating back to the sons of Edward III. The Lancastrian dynasty descended from John of Gaunt, third son of Edward III, whose son Henry deposed the unpopular Richard II. 

Yorkist claimants such as the Duke of York asserted their legitimate claim to the throne through Edward III’s second surviving son, but through a female line. The Wars of the Roses therefore tested whether the succession should keep to the male line or could pass through females.

Captured and briefly restored, Henry VI was captured and put to death, and the Yorkist faction led by Edward IV gained the throne.