On 11 August 1415, Henry sailed for France, where his forces besieged the fortress at Harfleur, capturing it on 22 September. Afterwards, Henry had to march with his army across the French countryside towards Calais. On 25 October 1415, on the plains near the village of Agincourt, he turned to engage a pursuing French army in battle. Despite his men-at-arms being exhausted and outnumbered, Henry led his men into battle, decisively defeating the French who died in the thousands. Most of those taken prisoners were slaughtered by order of Henry, who spared only the most illustrious. This victorious conclusion, from the English viewpoint, was only the first step in the campaign.