The English army (under its monarch Henry V) set sail from Southampton for France on August the 11th and landed on the North Bank of the Seine near the town of Harfleur (now part of Le Harve) on August 16th. Henry decided to start his campaign season by quickly besieging and capturing Harfleur. Harfleur would be difficult to capture in a siege because it was enclosed by a circuit of stone walls and towers with the ability to flood the ground to its west. Henry called on the town’s inhabitants to surrender in the hope of a quick victory, threatening to put them all to the sword if they declined. Despite this threat the garrison refused believing a French relief force would be dispatched. By the 24th of August the English frustrated by their slow progress in the siege began to bombard the town. It is interesting to note that the English forces had with them at least 5 cannon, a relatively new piece of equipment on the battlefield*. By 31st of August the English had begun to sink mines to collapse the French defences as they were becoming increasingly frustrated by the lack of progress.
By the third week of the siege (7 – 13th September) disease began to rear its ugly head in the English siege works. Medieval sanitation was not very well advanced and in most sieges disease caused more casualties than the actual fighting. The diseases affecting the English besieging force were most likely waterborne and caused by the flooding of the land around Harfleur itself. The effects of this on Henry’s army was devastating with significant losses to his force occurring (he sent at least 1500 ill men home). The mines sunk the week before to collapse the town’s defences were abandoned this week after they encountered enemy countermines.
A series of English assaults were launched in the fourth week of the siege (14th – 21st September) perhaps suggesting the dire need to quickly end the siege before Henry’s men succumbed to disease, French relief arrived or the campaign season ended. These assaults proved successful and on the 18th September an agreement was struck for a formal surrender of the garrison if French relief did not arrive by the 22nd September.
Without any sign of a French relief force having been arranged let alone marching to the garrison’s relief the town was surrendered as arranged on the 22nd September 1415. On the 24th September Henry ejected the populace of Harfleur giving them escort to Lillebonne where they were met and recieved by Marshal Boucicaut of the French army. The town would be repopulated with English settlers and garrisoned by 300 men-at-arms and 900 bowmen.
Whilst the siege of Harfleur was eventually successful, the five weeks it took to capture the town severely hampered Henry’s ability to carry his campaign towards Paris and bring the French to battle within the year’s campaign season. Similarly, the cost to Henry’s army had been significant with many men either lost in combat or succumbed to disease (the Earl March, Jon Mowbray, lost 31% of his 200 man retinue at Harfleur). Harfleur itself yielded little in the way of booty and Henry’s campaign had cost the English treasury a significant amount of money. At this point in time Henry’s campaign to recover the lands lost to England in France seemed to have been a failure but a bold decision was about to change all that.
*Gunpowder weapons were also used at the siege of Aberystwyth Castle (the town where I studied) and Harlech Castle in Wales earlier in the century.