The Battle of Pilckem Ridge (31 July – 2 August 1917) was the opening attack of the Third Battle of Ypres in the First World War. The British Fifth Army, supported by the Second Army on the southern flank and the French 1reArmée (First Army) on the northern flank, attacked the German 4th Army, which defended the Western Front from Lille northwards to the Ypres Salient in Belgium and on to the North Sea coast. On 31 July, the Anglo-French armies captured Pilckem (Flemish: Pilkem) Ridge and areas on either side, the French attack being a great success. After several weeks of changeable weather, heavy rain fell during the afternoon of 31 July.