The Battle of St. Quentin Canal was a pivotal battle of World War I that began on 29 September 1918 and involved British, Australian and American forces operating as part of the British Fourth Army under the overall command of General Sir Henry Rawlinson. Further north, part of the British Third Army also supported the attack. South of the Fourth Army's 19 km (12 mi) front, the French First Army launched a coordinated attack on a 9.5 km (6 mi) front. The objective was to break through one of the most heavily defended stretches of the German Siegfriedstellung (Hindenburg Line), which in this sector used the St Quentin Canal as part of its defences. The assault achieved its objectives (though not according to the planned timetable), resulting in the first full breach of the Hindenburg Line,