John of Gaunt: Portugal's Kingmaker
John of Gaunt's dynastic ambitions coincided with the urgent need of the Portuguese Crown for foreign support to secure its sovereign independence - the catalyst for a royal marriage and England's oldest alliance.
In July 1386 two men were dining on board ship in Plymouth Sound: the pair were John of Gaunt, Duke of Lancaster, uncle of the reigning Richard II and the most eminent and wealthy noble in England, and his son Henry of Bolingbroke, Earl of Derby, who was to usurp Richard's throne in 1399 as Henry IV. Gaunt set sail with the army with which he was to invade north-west Spain, in the hope of either establishing himself as King of Castile or honourably compromising his claim to its throne.