To claim the French throne, Henry V of England invaded France in 1415. Negotiations with the French had failed, which left him with no other choice but to invade.
He landed on 13 August 1415 in the Seine Estuary and laid siege to the port of Harfleur on 18 August 1415.
Harfleur was well protected by thick walls, towers, water defences and a garrison of men. It was also heavily populated and not prepared to surrender to English forces.
Thomas of Lancaster, 1st Duke of Clarence took part of the army and set up camp on the east side of the town, however before he could do this a French relief convoy managed to get through to reinforce the town.
The English having surrounded the town began to barrage it with artillery, badly damaging the walls. The town would still not surrender and spent time making repairs to their defences.
Many efforts were made by the English forces to bring the town to heel including digging tunnels under the walls or filling water ditches to make access across them easier, but none of these succeeded.
Having besieged the town for over a month, Henry V planned a full assault on 18 September 1515; the town however asked for a truce.
The leaders of the town stated that if the French army did not arrive by 23 September, the town would surrender to English forces.
Harfleur surrendered on 22 September 1415.
Although the English were victorious at Harfleur, many of Henry’s forces suffered sickness, which seriously depleted their numbers. The worse affected were allowed to return to England, however except for a small force left at Harfleur, the rest marched on towards Calais.