On 2 August 1914, the Belgian government refused the passage of German troops through Belgium to France and on the night of 3/4 August the Belgian General Staff ordered the 3rd Division to Liège to obstruct a German advance.
The German army invaded Belgium on the morning of 4 August.
Covered by the 3rd Division, the Liège fortress garrison, a screen of the Cavalry Division and detachments from Liège and Namur, the rest of the Belgian Field Army closed up to the river Gete and by 4 August the 1st Division had assembled at Tienen, the 5th Division at Perwez, the 2nd Division at Leuven and the 6th Division at Wavre, covering central and western Belgium and the communications towards Antwerp.
German cavalry appeared at Visé early on 4 August and found the bridge down and Belgian troops on the west bank.
The Germans found a ford, crossed the river and forced the Belgians to retire towards Liège.
By the evening it was clear to the Belgian High Command that the 3rd Division and the Liège garrison were in the path of a very large invasion force.

On 5 August the Battle of Liège began, when the Germans tried to capture the fortified city of Liège by a coup de main and then attempted a night attack, which collapsed in confusion until General Erich Ludendorff rallied the infantry.
Ludendorff attacked again around noon on 6 August and found no opposition in the city, the Belgian 3rd Division having been withdrawn to the Gete.
The Germans began a siege of the fortress, which fell on 16 August.
On 10 August German cavalry reached the Gete and Jägers began to move northwards to Diest and Hasselt.
On 12 August German cavalry and Jäger attacked at the Battle of Halen and were driven off after a ten-hour battle.
By 17 August, a huge number of German troops had crossed into Belgium between the Meuse, Demer and Gete, despite the demolitions carried out by the Belgian Army and paramilitary Garde Civique.
The Belgian position on the right (southern) flank of the Gete, was threatened by a flanking manoeuvre through Huy.
On 18 August the Germans attacked again, captured Halen, entered Tienen and attacked the 1st Division frontally and on the northern flank, which the 1st Division repulsed only with great difficulty.

With information that five German corps and six reserve corps were in Belgium and with no support from the French Army and British Expeditionary Force (BEF) ready, the Belgian Field Army was ordered to withdraw towards Antwerp on the evening of 18 August.
 It arrived on 20 August, with little interference from German advanced parties, except for an engagement between the 1st Division and the German IX Corps near Tienen, in which the Belgians had 1,630 casualties.
Brussels,  the Belgian capital,  was captured on 20 August, as the Belgian Field Army arrived at Antwerp.
 Namur fell on 24 August, at the same time that the field army made a sortie from Antwerp towards Brussels.
The Belgian government of Charles de Broqueville left Brussels and moved to Antwerp to avoid capture by the Germans, who detached the III Reserve Corps from the First Army to mask the city from positions either side of the Dyle Canal.
A brigade of the IV Reserve Corps was sent to occupy Brussels.
The IX Reserve Corps was ordered to move to Antwerp on 22 August.
On 2 August 1914, the Belgian government refused the passage of German troops through Belgium to France and on the night of 3/4 August the Belgian General Staff ordered the 3rd Division to Liège to obstruct a German advance. The German army invaded Belgium on the morning of 4 August. Covered by the 3rd Division, the Liège fortress garrison, a screen of the Cavalry Division and detachments from Liège and Namur, the rest of the Belgian Field Army closed up to the river Gete and by 4 August the 1st Division had assembled at Tienen, the 5th Division at Perwez, the 2nd Division at Leuven and the 6th Division at Wavre, covering central and western Belgium and the communications towards Antwerp. German cavalry appeared at Visé early on 4 August and found the bridge down and Belgian troops on the west bank. The Germans found a ford, crossed the river and forced the Belgians to retire towards Liège. By the evening it was clear to the Belgian High Command that the 3rd Division and the Liège garrison were in the path of a very large invasion force.
On 5 August the Battle of Liège began, when the Germans tried to capture the fortified city of Liège by a coup de main and then attempted a night attack, which collapsed in confusion until General Erich Ludendorff rallied the infantry. Ludendorff attacked again around noon on 6 August and found no opposition in the city, the Belgian 3rd Division having been withdrawn to the Gete. The Germans began a siege of the fortress, which fell on 16 August. On 10 August German cavalry reached the Gete and Jägers began to move northwards to Diest and Hasselt. On 12 August German cavalry and Jäger attacked at the Battle of Halen and were driven off after a ten-hour battle. By 17 August, a huge number of German troops had crossed into Belgium between the Meuse, Demer and Gete, despite the demolitions carried out by the Belgian Army and paramilitary Garde Civique. The Belgian position on the right (southern) flank of the Gete, was threatened by a flanking manoeuvre through Huy. On 18 August the Germans attacked again, captured Halen, entered Tienen and attacked the 1st Division frontally and on the northern flank, which the 1st Division repulsed only with great difficulty.
With information that five German corps and six reserve corps were in Belgium and with no support from the French Army and British Expeditionary Force (BEF) ready, the Belgian Field Army was ordered to withdraw towards Antwerp on the evening of 18 August.  It arrived on 20 August, with little interference from German advanced parties, except for an engagement between the 1st Division and the German IX Corps near Tienen, in which the Belgians had 1,630 casualties. Brussels,  the Belgian capital,  was captured on 20 August, as the Belgian Field Army arrived at Antwerp.  Namur fell on 24 August, at the same time that the field army made a sortie from Antwerp towards Brussels. The Belgian government of Charles de Broqueville left Brussels and moved to Antwerp to avoid capture by the Germans, who detached the III Reserve Corps from the First Army to mask the city from positions either side of the Dyle Canal. A brigade of the IV Reserve Corps was sent to occupy Brussels. The IX Reserve Corps was ordered to move to Antwerp on 22 August.
Siege of Antwerp (1914)