The situation
Henry V's campaign had taken Harfleur, but dysentery had gutted his army. Marching for Calais, he found a much larger French army blocking the road.
The decision
Henry accepted battle on ground that suited him: a recently ploughed field, soaked by rain, narrowing between the woods of Agincourt and Tramecourt. His archers drove sharpened stakes into the ground in front of them.
The French, confident in numbers, advanced on foot in heavy armour across the mud. The narrowing field crowded them together so tightly that many could not use their weapons, while arrows struck the flanks.
What it cost
French losses were catastrophic and fell heavily on the nobility; English losses were small. Controversially, Henry ordered prisoners killed during the battle when he feared a renewed attack. Agincourt made Henry's reputation and, through Shakespeare, became one of England's most retold victories.