On 6 August 1915, the 1st Australian Brigade launched an assault on the impregnable Ottoman position at Lone Pine. Led by the 2nd, 3rd and 4th Battalions (with the 1st Battalion held in reserve), the attack was orchestrated to divert Turkish attention and reinforcements away from the primary operation to the north of the line as the British sought to capture the Sari Bair ridge. The Australian assault at Lone Pine commenced in the late afternoon just before sunset. An artillery barrage had preceded the attack, though according to historian Robin Prior the results had been "feeble" and the advance was hard-fought. Nonetheless, within half an hour the Australians had breached the Turkish trenches and seized their objectives. Despite the initial success, Australian casualties had been heavy and the 1st Battalion was ordered forward in preparation for the expected Turkish counter-attack. The battle descended into fierce fighting over the next three days, often in the form of what Bryan Perrett has described as "deadly bombing duels".