of the King's Ships. Robert de Crull was the last to fill this position during EdwardIII's reign and would have the longest tenure in this position. It was during his tenure that Edward's naval administration would become a base for what evolved during the reigns of successors such as Henry VIII's Council of Marine and Navy Board and Charles I's Board of Admiralty. Rodger also argues that for much of the fourteenth century, the French had the upper hand, apart from Sluys in 1340 and, perhaps, off Winchelsea in 1350. Yet, the French never invaded England and King John II of France died in captivity in England. There was a need for an English navy to play a role in this and to handle other matters, such as the insurrection of the Anglo-Irish lords and acts of piracy. Crécy and Poitiers By the early 1340s, it was clear that Edward's policy of alliances was too costly, and yielded too few results. The following years saw more direct involvement by English armies, including in the Breton War of Succession, but these interventions also proved fruitless at first. Edward defaulted on Florentine loans of 1,365,000 florins, resulting in the ruin of the lenders. A change came in July 1346, when Edward staged a major offensive, sailing for Normandy with a force of 15,000 men. His army sacked the city of Caen, and marched across northern France, to meet up with English forces in Flanders. It was not Edward's initial intention to engage the French army, but at Crécy, just north of the Somme, he found favourable terrain and decided to fight a pursuing army led by PhilipVI. On 26 August, the English army defeated a far larger French army in the Battle of Crécy. Shortly after this, on 17 October, an English army defeated and captured King DavidII of Scotland at the Battle of Neville's Cross. With his northern borders secured, Edward felt free to continue his major offensive against France, laying siege to the town of Calais. The operation was the greatest English venture of the Hundred Years' War, involving an army of 35,000 men. The siege started on 4September 1346, and lasted until the town surrendered on 3August 1347. After the fall of Calais, factors outside of Edward's control forced him to wind down the war effort. In 1348, the Black Death struck England with full force, killing a third