On 12 October, the 12th Brigade was assigned to protect the 3rd Division's flank during the First Battle of Passchendaele, and took part in an effort to capture the Keiberg ridge. Although, elements of the 3rd were able to enter Passchendaele, and the 12th gained their objective, both groups were eventually forced back. The unsuccessful effort cost the 12th Brigade around 1,000 casualties. The Canadians then took over responsibility for the sector, and were eventually able to secure the village in November, while the Australians were withdrawn to Messines for a rest. In the wake of considerable losses, which could not be made up from voluntary recruitment, Australian authorities considered breaking up the 4th Division to provide reinforcements, although this did not eventuate. In November 1917, the division became part of the Australian Corps, initially under Lieutenant General William Birdwood and then later under Lieutenant General John Monash.