Belgian fortifications around Antwerp. On 1 October, the Germans attacked forts Sint-Katelijne-Waver and Walem and the Bosbeek and Dorpveld redoubts, held by the 5th Reserve and Marine divisions. By Fort Walem was severely damaged and Fort Lier was hit by shells but Fort Koningshooikt, the Tallabert and Bosbeek redoubts were mostly intact; the intervening ground between Fort Sint-Katelijne-Waver and Dorpveld redoubt had been captured. Despite reinforcement by the Royal Naval Division from 2 October, the Germans penetrated the outer ring of forts. When the German advance began to compress a corridor from the west of the city along the Dutch border to the coast, the Belgian field army withdrew from Antwerp westwards towards the coast. On 9 October, the remaining garrison surrendered and the Germans occupied the city. Some British and Belgian troops escaped to the Netherlands, where they were interned for the duration of the war. The Belgian withdrawal was protected by a French Marine brigade, Belgian cavalry and the British 7th Division around Ghent. On 15 October, the Belgian army occupied a defensive line along the Yser river in west Flanders, from Diksmuide to the coast. First Battle of the Marne, 5–12 September Joffre used the railways which had transported French troops to the German frontier to move troops back from Lorraine and Alsace to form a new Sixth Army under General Michel-Joseph Maunoury with nine divisions and two cavalry divisions. By 10 September twenty divisions and three cavalry divisions had been moved west from the German border to the French centre and left and the balance of force between the German and the Third, Fourth, Ninth, Fifth armies, the BEF and Sixth Army had changed to Late on 4 September, Joffre ordered the Sixth Army to attack eastwards over the Ourcq towards Château Thierry as the BEF advanced towards Montmirail and the Fifth Army attacked northwards, with its right flank protected by the Ninth Army along the St. Gond marshes. The French First, Second, Third and Fourth armies to the east, were to resist the attacks of the German between Verdun and Toul and repulse an enveloping attack on the defences south of Nancy from the north. The 6th and 7th armies were reinforced by heavy artillery from Metz and attacked again on 4 September along the Moselle. On 5 September, the Sixth Army advanced eastwards from Paris and met the German IV Reserve Corps, which had