The Battle of Mont Saint-Quentin was a battle on the Western Front during World War I. As part of the Allied Hundred Days Offensive on the Western Front in the late summer of 1918, the Australian Corps crossed the Somme River on the night of 31 August and broke the German lines at Mont Saint-Quentin and Péronne. The British Fourth Army's commander, General Henry Rawlinson, described the Australian advances of 31 August – 4 September as the greatest military achievement of the war. During the battle Australian troops stormed, seized and held the key height of Mont Saint-Quentin (overlooking Péronne), a pivotal German defensive position on the line of the Somme.