For six centuries, Harfleur was the principal seaport of north-western France. In 1415, it was captured by Henry V of England, an event explicitly mentioned in a popular song of the day, the Agincourt Carol. Sir John Fastolf of Caister Castle Norfolk (1380–1459) later claimed to have been 'the first man over the side' of the boat when the English landed outside the town; and he certainly played a part in the siege, being invalided home afterwards. The Siege of Harfleur lasted some weeks longer than Henry V had anticipated; that was not helped by the outbreak of dysentery which afflicted and killed soldiers, knights, and nobles, with many of the sick having to be transported back to England. The town's defences were badly damaged by the siege warfare, as were many of the principal buildings of the town. In order to consolidate his victory, Henry was forced to leave a significant part of his army as a garrison for the newly captured town. Whilst Henry's intentions after the end of the siege are unclear, he had clearly entered France with an army large enough to engage the French in open battle and not merely to lay siege to one town. Henry left Harfleur, but he found his path to Calais blocked by a French army forcing him inland. The French cut off the English route and confronted them on the muddy fields near Azincourt (not the present-day Agincourt) on Saint Crispin's Day, 25 October 1415. The Battle of Agincourt ended in a decisive English victory with minimal losses - only in the hundreds - and a crushing defeat for the French with losses nearing the tens of thousands.