In January 1916, in the aftermath of the Gallipoli Campaign, the Australian government decided to expand the Australian Imperial Force, then based in Egypt, prior to the force's deployment to the Western Front. At the time, two divisions already existed in Egypt: the 1st and 2nd. The 3rd Division was also being raised in Australia. The 2nd Division had only been partially raised by the time it was sent to Gallipoli late in the campaign, so it was left to complete its formation, while the 1st Division, and the spare 4th Brigade (which had formed part of the composite New Zealand and Australian Division and had served at Gallipoli) were used to provide an experienced cadre to form the 4th and 5th Divisions. The 4th Division subsequently gained the experienced 4th Brigade, and two newly raised brigades – the 12th and 13th – which were formed from cadres from the 4th and 3rd Brigades respectively.