The combined Flemish forces met at Kortrijk on 26 June and laid siege to the castle, which housed a French garrison.
As the siege was being laid, the Flemish leaders began preparing a nearby field for battle.
The size of the French response was impressive, with 3,000 knights and 4,000–5,000 infantry being an accepted estimate.
The Flemish failed to take the castle and the two forces clashed on 11 July in an open field near the city next to the Groeninge stream.

The field near Kortrijk was crossed by numerous ditches and streams dug by the Flemish as Philip's army assembled.
Some drained from the river Leie (or Lys), while others were concealed with dirt and tree branches, making it difficult for the French cavalry to charge the Flemish lines.
The marshy ground also made the cavalry less effective.
The French sent servants to place wood in the streams, but they were attacked before they completed their task.
The Flemish placed themselves in a strong defensive position, in deeply stacked lines forming a square.
The rear of the square was covered by a curve of the river Leie.
The front presented a wedge to the French army and was placed behind larger rivulets.

The 1,000 French crossbowmen attacked their 900 Flemish counterparts and succeeded in forcing them back.
Eventually, the French crossbow bolts and arrows began to hit the main Flemish infantry formations' front ranks but inflicted little damage.

The French commander Robert of Artois was worried the outnumbered French foot would be attacked from all sides by superior, heavily armed Flemish infantry on the other side of the brooks.
Furthermore, the Flemish would then have their formations right on edge of the brooks and a successful French cavalry crossing would be extremely difficult.
He therefore recalled his foot soldiers to clear the way for 2,300 heavy cavalry arranged into two attack formations.
The French cavalry unfurled their banners and advanced on the command "Forward!".

Some of the French footmen were trampled to death by the armoured cavalry, but most managed to get back around them or through the gaps in their lines.
The cavalry advanced rapidly across the streams and ditches to give the Flemish no time to react.
The brooks presented difficulties for the French horsemen and a few fell from their steeds.
Despite initial confusion, the crossing was successful in the end.
The French reorganized their formations on the other side to maximize their effectiveness in battle.

Ready for combat, the French knights and men-at-arms charged at a quick trot and with their lances ready against the main Flemish line.
The Flemish crossbowmen and archers fell back behind the pikemen.
A great noise rose throughout the dramatic battle scene.
The disciplined Flemish foot-soldiers kept their pikes ready on the ground and their goedendags raised to meet the French charge.
The Flemish infantry wall did not flinch and a part of the French cavalry hesitated.
The bulk of the French formations carried on their forward momentum and fell on the Flemish in an ear-splitting crash of horses against men.
Unable at most points to break the Flemish line of pikemen, many French knights were knocked from their horses and killed with the goedendag, the spike of which was designed to penetrate the spaces between armour segments.
Those cavalry groups that succeeded in breaking through were set upon by the reserve lines, surrounded and wiped out.

To turn the tide of the battle, Artois ordered his rearguard of 700 men-at-arms to advance, joining the battle personally with his own knights and with trumpets blaring.
The rearguard did not attack the Flemish however, remaining stationary after its initial advance to protect the French baggage train.
Artois' charge routed some of the Flemish troops under Guy of Namur, but could not break the entire Flemish formation.
Artois' men-at-arms were attacked by fresh Flemish forces and the French fought back with desperate courage, aware of the danger they were in.
Artois defended himself skillfully.
His horse was struck down by a lay brother, Willem van Saefti
The combined Flemish forces met at Kortrijk on 26 June and laid siege to the castle, which housed a French garrison. As the siege was being laid, the Flemish leaders began preparing a nearby field for battle. The size of the French response was impressive, with 3,000 knights and 4,000–5,000 infantry being an accepted estimate. The Flemish failed to take the castle and the two forces clashed on 11 July in an open field near the city next to the Groeninge stream.
The field near Kortrijk was crossed by numerous ditches and streams dug by the Flemish as Philip's army assembled. Some drained from the river Leie (or Lys), while others were concealed with dirt and tree branches, making it difficult for the French cavalry to charge the Flemish lines. The marshy ground also made the cavalry less effective. The French sent servants to place wood in the streams, but they were attacked before they completed their task. The Flemish placed themselves in a strong defensive position, in deeply stacked lines forming a square. The rear of the square was covered by a curve of the river Leie. The front presented a wedge to the French army and was placed behind larger rivulets.
The 1,000 French crossbowmen attacked their 900 Flemish counterparts and succeeded in forcing them back. Eventually, the French crossbow bolts and arrows began to hit the main Flemish infantry formations' front ranks but inflicted little damage.
The French commander Robert of Artois was worried the outnumbered French foot would be attacked from all sides by superior, heavily armed Flemish infantry on the other side of the brooks. Furthermore, the Flemish would then have their formations right on edge of the brooks and a successful French cavalry crossing would be extremely difficult. He therefore recalled his foot soldiers to clear the way for 2,300 heavy cavalry arranged into two attack formations. The French cavalry unfurled their banners and advanced on the command "Forward!".
Some of the French footmen were trampled to death by the armoured cavalry, but most managed to get back around them or through the gaps in their lines. The cavalry advanced rapidly across the streams and ditches to give the Flemish no time to react. The brooks presented difficulties for the French horsemen and a few fell from their steeds. Despite initial confusion, the crossing was successful in the end. The French reorganized their formations on the other side to maximize their effectiveness in battle.
Ready for combat, the French knights and men-at-arms charged at a quick trot and with their lances ready against the main Flemish line. The Flemish crossbowmen and archers fell back behind the pikemen. A great noise rose throughout the dramatic battle scene. The disciplined Flemish foot-soldiers kept their pikes ready on the ground and their goedendags raised to meet the French charge. The Flemish infantry wall did not flinch and a part of the French cavalry hesitated. The bulk of the French formations carried on their forward momentum and fell on the Flemish in an ear-splitting crash of horses against men. Unable at most points to break the Flemish line of pikemen, many French knights were knocked from their horses and killed with the goedendag, the spike of which was designed to penetrate the spaces between armour segments. Those cavalry groups that succeeded in breaking through were set upon by the reserve lines, surrounded and wiped out.
To turn the tide of the battle, Artois ordered his rearguard of 700 men-at-arms to advance, joining the battle personally with his own knights and with trumpets blaring. The rearguard did not attack the Flemish however, remaining stationary after its initial advance to protect the French baggage train. Artois' charge routed some of the Flemish troops under Guy of Namur, but could not break the entire Flemish formation. Artois' men-at-arms were attacked by fresh Flemish forces and the French fought back with desperate courage, aware of the danger they were in. Artois defended himself skillfully. His horse was struck down by a lay brother, Willem van Saefti
Battle of the Golden Spurs