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 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.