Its goals could be multiple.
Destroy economic resources.
Seize goods.
Burn crops.
Damage towns.
Take prisoners.
Force local nobles to choose sides.
Humiliate the enemy king by demonstrating that he could not defend his subjects.
Perhaps provoke the enemy into offering battle under unfavorable conditions.
This was not a gentle form of warfare.
For ordinary people living in the path of such armies, the campaign could mean lost harvests, stolen animals, burned buildings, forced payments, displacement, and fear.
The aristocratic language of chivalry did not protect villages from armies living off the land.
Edward's campaign was effective partly because it imposed those costs deliberately.
As the prince moved through France, every damaged settlement created political pressure on John II.
A king who allowed foreign troops to burn his territories without punishment risked appearing powerless.
Edward understood that.
John understood it too.
The French king could not simply allow the Anglo-Gascon army to wander home comfortably after devastating the countryside.
He needed to catch it.
The campaign therefore became a race between one army trying to maintain mobility and another trying to remove it.
For a time, Edward kept moving.
Then geography interfered.
The Loire Became a Wall
Rivers dominate medieval military movement far more than maps often suggest.
A modern reader sees a blue line and imagines crossing.
An army sees thousands of men, horses, wagons, weapons, supplies, prisoners, and animals that all need to reach the other bank.
Bridges become strategic prizes.
Fords depend on water level.
Defenders can destroy crossings.
Heavy rain can transform a manageable stream into a barrier.
Edward moved northward hoping for opportunities beyond the Loire, perhaps including cooperation with other English forces.
The crossings available to him were either defended, inaccessible, or otherwise unsuitable.
His strategic plan narrowed.
He turned south.
That reversal gave the French a chance.
John II moved rapidly enough to bring his royal army toward the road Edward needed.
The French king was not simply chasing blindly from behind.
He was maneuvering to intercept.
When the armies approached Poitiers, Edward discovered that the route toward Bordeaux was no longer open in the way he wanted.
Retreat was becoming dangerous.
The prince could attempt to move around the French.
He could negotiate.
He could choose ground and fight.
None was attractive.
The presence of a much larger enemy army makes every option unpleasant.
The Army Edward Commanded Was Not Simply English
Modern national labels can obscure the composition of medieval forces.
Edward served the English crown, but his army relied heavily on Gascon nobles and soldiers from territories in southwestern France.
For those men, the conflict was not necessarily a simple foreign invasion of France by England.
Their own lands, rights, rivalries, and loyalties shaped participation.
Gascon commanders provided local knowledge and military ability.
One of the most important figures associated with Poitiers was Jean III de Grailly, the Captal de Buch, a powerful Gascon noble whose later maneuver during the battle would contribute to French collapse.
Edward therefore commanded a coalition bound together by English royal authority, regional interests, shared campaigning, and the opportunities war offered.
That coalition had been riding and fighting for weeks.
Its strength depended not merely on numbers but on experience.
Many men knew how to operate in mobile campaigns.
Archers knew how to move with mounted armies.
Men-at-arms were prepared to dismount and fight defensively when required.
Commanders understood the value of terrain.
This experience would matter because Poitiers demanded rapid transition.
Raiders had to become defenders.
Defenders would later become attackers.
An army unable to change roles quickly could not have survived.
The Negotiations Before Battle
On September 18, attempts were made to prevent the fighting.
Cardinal Hélie de Talleyrand-Périgord, acting as a papal mediator, moved between the two armies.
The Church had strong reasons to prefer negotiation between Christian rulers, while the wider political world had no shortage of other threats and conflicts demanding attention.
Different sources describe the proposed terms differently, and specific details should be treated cautiously.
Edward appears to have been willing to consider concessions.
John believed he held the advantage.
The French king had caught the raiding army.
He had more troops.
The enemy was far from home.
Allowing Edward simply to leave would make the entire pursuit seem pointless.
The French king therefore demanded conditions the prince would not accept.
Negotiation failed.
Later English narratives could present this as French arrogance.
That interpretation is too convenient.
John's confidence had rational foundations.
Imagine the situation without knowing the outcome.
A smaller hostile army has been cornered after weeks of raiding.
Its commander wants to escape.
Your larger royal force stands between him and safety.
Why accept weak terms?
A commander can be reasonable and still be wrong.
John's mistake was not that he believed the French possessed advantages.
They did.
The problem was assuming those advantages would survive contact with Edward's chosen ground.
The Battlefield Was Not an Empty Plain
Poitiers is sometimes imagined as two armies simply facing one another across open space.
The actual environment mattered enormously.
Vineyards divided the fields.
Hedges restricted visibility and movement.
Roads and lanes created natural channels.
Uneven cultivated terrain complicated large-scale maneuvers.
Edward positioned his army so that the French could not use every soldier at once.
That is the central tactical idea.