 Complete the following phrase:  The 1st Divisions role in the August Offensive was to hold the front line and conduct a diversion on 400 Plateau at Lone Pine on 6 August. The resulting battle was the only occasion when a significant length of the Turkish trench line was captured, but resulted in heavy casualties. The main assault was made by the 1st Brigade, which was later reinforced by the 7th and 12th Battalions. Out of an assault force of 2,900 men, 1,700 were killed or wounded. On 7 August, the 6th Battalion from the 2nd Brigade made an unsuccessful attempt to capture the German Officers Trench as a preliminary operation to other assaults by light horsemen at Quinns Post and 