Halen (Haelen in French) was a small market town and a convenient river crossing of the Gete and was situated on the principal axis of advance of the Imperial German army.

Belgian general headquarters chose Halen as a place to delay the advance and gain time to complete an orderly retreat to the west.

[2] The German II Cavalry Corps (Höheres Kavallerie-Kommando2 [HKK 2]) commanded by General Georg von der Marwitz, was ordered to conduct reconnaissance towards Antwerp, Brussels and Charleroi.

To block this advance, the Belgian Cavalry Division, commanded by Lieutenant-General Léon de Witte, was sent to guard the bridge over the River Gete at Halen.

During an evening meeting, the Belgian general staff convinced de Witte to fight a dismounted action to negate the German numerical advantage.

This was the former train connexion between the towns of Tienen and Diest, still prominent nowadays, partly coinciding with Sportlaan and Stadsbeemd streets and further used as a tourist cycle track.

[7] General De Witte had been reconnoitring in the provinces of Liège and Limburg and his cavalry division was also responsible for the defence of the long and vulnerable east flank of the Belgian army.

On the night of 11/12 August, De Witte and his staff decided that, on the following day, lancers and scouts would fight dismounted with their carbines at the recommendation of two young officers, Commander Tasnier and Lieutenant Van Overstraeten.

[8] It was only in the early hours of the 12 August that the Belgian army command at Leuven realised that the Germans were directing large amounts of infantry and cavalry to Halen.

The German cavalry did not begin to move until 12 August due to the fatigue of the horses caused by the intense summer heat and a lack of oats.

At 7:00 a.m., the Belgian Headquarters discovered from intercepted wireless messages that German troops were advancing towards de Witte's position and sent the 4th Mixed Brigade to reinforce the Cavalry Division.

The pressure of the German infantry attacks made their position untenable; around noon the soldiers retreated on foot through fields, to join the main force of the division.

The road was lined with hedges and had been fenced off with barbed wire, forcing the dragoons to make a frontal attack; a great number of them were killed, wounded or captured.

Overstraeten feared they were retreating too fast and ordered the carabineer-cyclists to return to the sunken road and take up new positions there but the German cavalry were already advancing through the fields.

Over the next two hours, regiments of dragoons, cuirassiers and uhlans appeared on the battlefield in the same order as they had crossed the Gete river and charged with lance and sabre.

Backed by their artillery near Halen station and in the village of Velpen, the German infantry attacked the farm and eventually overwhelmed the defenders.

Colonel Dujardin was severely wounded at Zelk but Lieutenant van Dooren, of the 4th Regiment of Mounted Chasseurs, succeeded with a few men in silencing the German artillery along the road to Halen.

Around 7:00 p.m., IJzerwinning farm was recaptured and De Witte then ordered a counterattack on Velpen and Halen to push the enemy back to the right bank of the river Gete.

The inexperienced infantry blindly attacked towards the village of Velp, where German machine-gunners had taken cover in a number of houses and farms, and were repulsed.

On 16 August, Marwitz advanced with the two divisions to Opprebais and Chaumont-Gistoux, where skirmishing with cavalry and artillery occurred, before meeting infantry who were well dug-in.