When the battles of the Sambre and Mons were raging, the Belgian field army suddenly made a sortie from Antwerp, in order to menace the Germans in the rear. They had a great fight on a line between Vilvorde and Aerschot, but, having no large guns, did not succeed in breaking through the German observation army which covered the line from Liège to Brussels. They made a second sortie on September 9. They succeeded in recapturing Aerschot and were about to retake Louvain, when German reinforcements stopped their advance. This sortie retained in Belgium important German reinforcements, which were on their way to restore the German fortunes on the Marne. The German General Staff frankly admits the importance of this move on the part of the Belgian army. A third sortie did not succeed, for, exactly at this time (September 27), the Germans began the siege of Antwerp. They wanted to put an end to these continuous threats on their rear and their communication lines with Germany. Just as Liège and Namur fell under the fire of the 30.5- and 42.0-centimeter guns, Antwerp proved irremediably lost after two or three days’ bombardment. The British marine fusiliers and men of the Naval Reserve, sent by Churchill with the hope of delaying the fall of the fortress, could merely support the morale of the Belgian defenders by their presence, but that was all. On the evening of October 6 the Belgian field army, under the personal conduct of King Albert, succeeded in leaving Antwerp without the Germans being aware of it. The city continued to be defended by the garrison troops and the British. After a terrible bombardment of thirty-six hours the last defenders escaped in their turn, and on October 9 the civilian authorities surrendered the town to General von Beseler. The Germans boasted of the great war spoils found in the town, but they were extremely angry to find the city empty of troops. The Belgian field army, meanwhile, accomplished a very dangerous but admirably conducted retreat through Flanders, and stopped on the Yser, on October 14-15. The soldiers were exhausted. They had barely taken up their position along the little river when a mighty German army, composed partly of some corps of von Beseler’s army, partly of fresh troops--mostly university men, volunteers--just arrived from Germany, appeared, with the aim of breaking through in the direction of Dunkirk and Calais.