A large army of King Philip VI of France numbering some 30,000 to 40,000 men, was in close pursuit of King Edward III. The latter had had to cross the Somme river at a ford known as Blanchetacque, downstream of Abbeville.

This had to be undertaken at low tide, leaving a detachment of the French army and Genoese crossbowmen on the North shore time to prepare.

Longbowmen were the first to wade in to a volley of crossbow bolts. They overcame the opposition at considerable cost.

The English in turn now left a rearguard on the North shore while the tide rose and stopped the main French army coming up behind them. The English army moved swiftly North-west to take and despoil le Crotoy on the other (North) shore of the Somme estuary. They also cleared much of the countryside of resistance towards the East.

The main French Army, unable to make the crossing at the same ford, moved South-eastwards inland to Abbeville. The following day much of the French army, which included 6000 Genoese crossbowmen as well as some and German mercenaries, proceeded North-west from Abbeville to the Crotoy. Smoking fires had encouraged them into thinking the English were still in the town and could be encircled. However, the English Army had moved on and was already making defensive preparations for a battle at Crécy. The considerable detour thereby made by the French army meant that by the time it located the English, it had already marched an appreciable distance. 

In the meantime the English Army numbering some 12,000 to 13,000 of which 6000 to 7000 were longbow men, was aligned on a ridge between Crécy and Wadicourt. The ground in front of the Crécy-Wadicourt ridge slopes away to a shallow valley with a small river. Just below the ridge the ground has up to three terraces in some places. The steepest part of the ridge is towards Crécy, while towards Wadicourt the fall of the ground softens and is marshy at the bottom. Woods at either end afforded some protection to the flanks, while a small wood behind the battle lines was used to locate the baggage train. The battle line was some 2000 yards (1830m) long, which given the numbers deployed was a comparatively narrow front. King Edward had chosen his ground well and now made expert use of it.

The English Army was drawn-up in three battle lines, two in the front-line and one in reserve. Each line consisted of a centre of dismounted knights and men at arms, flanked on both sides by forward curving wings of archers. The English capitalised on the lie of the land and in its occupation of the terraces. The forward line with equal numbers of archers on its wings stood at the edge of the gradually rising ground. The second line was nearer the ridge. The King held the third line a short distance back from the ridge itself and was quartered in a windmill overlooking the whole of the battlefield.

Given the length of the front and the numbers it had to accommodate it is likely that the English positioned their longbow men in wedge-shaped formations. The wedge or harrow-formation was varied in order to take account of the ground, but the majority of archers were on the flanks in an open V formation pointing towards the adversary. Placed in wedge-shaped ranks a thicker barrage of arrows was possible and this was a vital contributor to the outcome of the battle. Each longbow man carried two sheafs of 24 arrows. The method of re-supply was well rehearsed with archers going a short distance for supplies, while others took their place. Runners covered the distance between the archers and the baggage train.

The English army had good time to prepare itself, not only in terms of its disposition, but also to add to its defences with ditches, potholes and caltrops placed in the ground ahead of it.

The army was fully dismounted and had been given strict instructions not to pursue the enemy too far down the slope into the valley. The discipline it showed in not doing so was critical.

The advance for the French up to the ridge was some 500 yards (460m), of which 400 (366m) on upward sloping terrain. The slope increases as one approaches the first of the terraces. The French Army was sighted from the windmill at about four in the afternoon. The Oriflamme had been unfurled signifying that no quarter was to be given. However, King Philip's advisors counselled against joining battle that same day for two reasons. Only four hours of daylight remained and the army needed resting after a long march. Secondly the size of the Army was such that during the march columns had become mixed up and needed organising prior to battle. King Philip accepted the advice. However, the nobles seeing the English up on the ridge and confident of an easy victory, could not resist pressing for an immediate attack. As the cavalry and men at arms on foot surged forward the French King had to give way and agree to the charge, which therefore got underway without proper order.

Moments prior to the battle there was a thunderstorm with a heavy downpour, which softened the ground, making it heavier for the cavalry. It also loosened the heavy bowstrings on the crossbows of the Genoese mercenaries in the French army. This may to some extent have spoilt their cast. The longbow men in the English lines had tucked theirs under their helmets to keep them dry. When the sun came out again it was on the backs of the English and therefore shone straight into the eyes of the attacking forces.

It is possible that in the haste to attack the Genoese crossbow men had not been able to retrieve their pavises (large shields) from the baggage train. If that were so it would have left them without protection once they had shot and were starting to reload. The 6000 Genoese crossbow men were placed in a forward position and were followed up the gradually inclining slope by the cavalry. Crossbows at that time were made of wood or composite construction and shot approximately 200 to 220 yards (180-200 metres). When the crossbow men had the forward lines of the English within that distance they loosed their bolts. The flat trajectory of a crossbow bolt, pointed slightly upwards to meet the rising ground, meant that much of the shot missed the English who were partially hidden from view on the terraces.

Little did the Genoese realise that the longbow had the greater range and could cover up to 320 yards (300 metres). While the slow process of reloading their crossbows began after the first round, the English longbow men stood up and shot volley after volley of arrows.