Two days later, on ground of their choosing, the English inflicted a heavy defeat on the French at the Battle of Crécy on 26 August 1346, before moving on to besiege Calais.

There was a further week's delay while the King and his council debated what to do, by which time it proved impossible to take any action with the main English army before winter.

In spite of borrowing over 330,000 florins (£61 million in 2025 terms[note 1]) from the Pope, orders were issued to local officials to: "Amass all of the money you can for the support of our wars.

Duke John of Normandy, the son and heir of Philip VI, was placed in charge of all French forces in south-west France, as he had been the previous autumn.

It had long been the case that all Englishmen of military age could be called to arms to defend the country against invaders; in early 1346 this was extended to a requirement to also serve overseas.

[34] Edward exempted the counties north of the River Humber from sending men to join the invasion force, and some limited financial commitments were made to them.

In an attempt to make up the numbers, the previous year's expedient of permitting convicted felons to enrol on the promise of a pardon if they served for the duration of the campaign was repeated, with up to a thousand being recruited.

By English common law, the king was required to compensate the owners of ships impressed into service, but in practice he paid little and late, which caused shipowners to be reluctant to answer summonses to arms.

[67][68] While wishing to seize the movable wealth of the areas he crossed, Edward issued strict instructions that no ecclesiastical properties were to be looted, no civilians were to be harmed, and no buildings were to be burnt; he set up a clear enforcement mechanism.

[69][70] Once on the march, English soldiers set fire to every town in their path, looted whatever they could from the populace and from private and ecclesiastical establishments and frequently raped the women.

The English fleet paralleled the army's route, devastating the country for up to 5 miles (8 km) inland and taking vast amounts of loot; many ships deserted, their crews having filled their holds.

[76] Raoul, Count of Eu, who was the Grand Constable of France, the senior position in the French military hierarchy, had been hastily transferred north from Aiguillon.

[76] He decided to resist the English at Caen, the cultural, political, religious and financial centre of north-west Normandy, larger than any town in England except London.

[80] On 29 July Edward sent his fleet back to England, with a letter ordering that reinforcements, supplies and money be collected, embarked and loaded respectively, and sent to rendezvous with his army at Crotoy, on the north bank of the mouth of the River Somme.

On 2 August a small English force commanded by Hugh Hastings and supported by many Flemings invaded France from Flanders; French defences here were completely inadequate.

After a furious argument with his advisers, and according to some accounts his father's messenger, Duke John refused to move until Aiguillon fell and his honour was satisfied; the main French army remained tied down in the south west.

[92] Philip, under pressure from two cardinals sent by Pope Clement, sent envoys offering peace backed by a marriage alliance; Edward replied that he was not prepared to lose marching time to futile discussion and dismissed them.

[102][103] In anticipation of such a move, the French had carried away all stores of food from the region the English were advancing into, forcing them to spread out over a wide area to forage, which greatly slowed them.

[104][105] Edward needed to break the French blockade of the Somme and probed at several points, vainly attacking Hangest and Pont-Remy before moving west along the river.

[113][114] While waiting for the French to catch up with them the English fortified their baggage camp, dug pits in front of their positions and set up several primitive gunpowder weapons.

[121] The battle was reported to the English Parliament on 13 September in glowing terms as a sign of divine favour and as a justification for the huge cost of the war to date.

They continued to devastate the land, and set several towns on fire, including Wissant, the normal port of disembarkation for English shipping to north-west France.

[135] Calais was strongly fortified; being surrounded by extensive marshes, some of them tidal, which made it difficult to find stable platforms for trebuchets and other artillery capable of breaching its walls.

[142] Among other consequences, this equivocation allowed Lancaster in the south-west to launch offensives into Quercy and the Bazadais; and himself lead a chevauchée 160 miles (260 km) north through Saintonge, Aunis and Poitou, capturing numerous towns, castles and smaller fortified places and storming the rich city of Poitiers.

Believing that Lancaster was heading for Paris, the French changed the assembly point for any men not already committed to Compiègne to Orléans, and reinforced them with some of those already mustered, to block this.

[152] Recriminations were rife: officials at all levels of the Chambre des Comptes (the French treasury) were dismissed and all financial affairs were put into the hands of a committee of three senior abbots.

[153] Between mid-November and late February Edward made several attempts to breach the walls with trebuchets or cannon, and to take the town by assault, either from the land or seaward side; all were unsuccessful.

[155] Philip attempted to take the field in late April, but the French ability to assemble their army in a timely fashion had not improved since the autumn and by July it had still not fully mustered.

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

[169][170] Edward granted Calais numerous trade concessions and privileges and it became the main port of entry for English exports to the continent, a position which it still holds.