It is hard to imagine the coast below the attractive Sussex town of Winchelsea as the site of a fierce naval battle, yet that is exactly what it was at the halfway point of the 14th century. On 29 August 1350, just as Europe was beginning to recover from the ravages of the Black Death, the fleets of England and Castile clashed in the English Channel. The piracy of Castilian vessels, marauding as far away from the Iberian peninsula as the waters around Flanders, was a well-known peril in the northern seas but, on this occasion, it was the Spanish alliance with England’s traditional enemy, France, that had led to conflict. The English fleet that August day, commanded by the Black Prince, won a victory that is less well known than the English triumph at the Battle of Sluys ten years earlier but is nevertheless of great significance. Its importance lay not just in the considerable loss of life and ships on the Castilian side but also in the permanent weakening of the Franco-Castilian alliance. This came as a relief to the English king, Edward III, vindicating his confidence in his eldest son. It was also the first taste of warfare for his third son, ten-year-old Prince John, who was aboard the Black Prince’s ship, in the thick of the fighting.

Prince John came to be known as John of Gaunt, after his birthplace, Ghent, in what is now Belgium. The name will be forever associated with Shakespeare’s Richard II, in which John of Gaunt, ageing and at odds with his wilful nephew, delivers one of the most famous of all Shakespearean speeches, lamenting the ruination of Richard’s rule in England, ‘this precious stone set in the silver sea’. It is a brilliant speech – and, no doubt, the real Gaunt would have delighted in such eloquence – but those who have used it as a paean to the glories of England might be less than delighted to learn that the real Gaunt devoted a large part of his life to attempting to become king of Castile. Like most medieval grandees his ambition was to acquire land and power and the riches that came with them. There was a limit to what England could offer him so he looked to continental Europe. As with most English royalty since the Norman Conquest, he needed