The English king, Edward III, became aware of the plot and personally led his household knights and the Calais garrison in a surprise counter-attack.

[6][7] After retreating in the face of Philip's large and increasing army, the English turned to fight at the Battle of Crécy, where the French were defeated with heavy loss.

With French finances and morale at a low ebb after Crécy, Philip failed to relieve the town, and the starving defenders surrendered on 3 August 1347.

Negotiations began in early September and by the 28th the Truce of Calais, intended to bring a temporary halt to the fighting, had been agreed.

[16][17] Calais was vital to England's effort against the French for the rest of the war, it being all but impossible to land a significant force other than at a friendly port.

Earlier, in 1340, Edward's forces had to fight a French fleet larger than his to gain access to the port of Sluys to disembark his army.

[18][19] The town had an extremely strong standing garrison of 1,200 men,[20] virtually a small army,[21] under the command of the captain of Calais.

[29] The truce facilitated contact and Charny reasoned that, as a man of low status, Amerigo would be more susceptible to avarice and as a non-Englishman, he would have fewer scruples regarding treachery.

To maintain secrecy the expedition was carried out under the titular command of Sir Walter Manny, previously the first captain of Calais.

The gate controlled by Amerigo was too difficult of approach to be used by such a large force, although it provided easy access to the harbour for ship's crews.

[43] Even to get as far as Amerigo's gate would be difficult; Calais was surrounded by a broad belt of marshes, and the few roads through them were controlled by English blockhouses.

[17] The French came up with a plan to set off on New Year's Eve, when the hours of darkness would be close to their maximum, low tide would be shortly before dawn, and the English sentries and garrisons might be caught celebrating or sleeping.

[44] The leader of the group to enter through Amerigo's gate was Oudart de Renti, a French knight who had been banished, joined the English and been given a command in the army of 20,000 Flemings who supported Edward's siege of Calais.

In 1347 he was pardoned by Philip, turned his coat again and was appointed by Charny because of his detailed knowledge of the area around Calais, and to give him an opportunity to redeem his honour.

[48][49][note 6] At the sound of a trumpet the Boulogne Gate was opened and Edward, in plain armour and under Walter Manny's banner, led out his household troops, supported by a detachment of archers, and attacked the French.

[61] As he had fought in the front rank, Edward claimed many of the prisoners as his own, including Charny, whose captor he rewarded with a gratuity of 100 marks[note 8] (approximately £80,000 in 2023 terms).

[34] He was also the keeper of the Oriflamme, the French royal battle banner;[34] the requirements of this office included being "a knight noble in intention and deed ... virtuous ... and chivalrous".

The modern historian Jonathan Sumption reports that the whole affair was so embarrassing that French participants were said to have "maintained a tight-lipped silence" regarding their roles in it.

[54] The amount is not known, but King John II (r. 1350–1364), Philip's son and successor after his father's death during Charny's imprisonment,[71] made a partial contribution of 12,000 écus (approximately £2,100,000 in 2023 terms).

[72] During his captivity Charny wrote much of his famous Book of Chivalry (Livre de chevalerie), in which he warns against turning to "cunning schemes" as opposed to actions which are "true, loyal and sensible".

Guînes was of little financial value to Raoul, and it was clear that Edward was prepared to accept it only in lieu of a full ransom payment because of its strategic position.

[74][75] Angered by the attempt to weaken the blockade of Calais, the new French king, John II, promptly had Raoul executed for treason.

The French were furious, the acting-commander was drawn and quartered for dereliction of duty at Charny's behest, and a strong protest was sent to Edward.

Several members of the King's Council made fiery, warmongering speeches and the parliament was persuaded to approve three years of war taxes.

[82] The English had been strengthening the defences of Calais with the construction of fortified towers or bastions at bottlenecks on the roads through the marshes to the town.

It was felt that his service at Calais had earned him a position of responsibility, but he was not trusted enough to be assigned to any place where a betrayal would be a devastating blow.

In July the Calais garrison launched a surprise night attack on Charny's army, killing many Frenchmen and destroying their siege works.

[84] Shortly after, Charny abandoned the siege and marched his army to Fretun where it launched a surprise attack during the night of 24/25 July.

[84] Before they departed they gathered, together with the populace from miles around, to witness Amerigo being tortured to death with hot irons and quartered with an axe; his remains were displayed above the town gates.

[87] Charny was killed in 1356 at the Battle of Poitiers, when the French royal army was defeated by a smaller Anglo-Gascon force commanded by the Black Prince, and John was captured.