Dobell launched the Second Battle of Gaza in April 1917 with a full scale frontal assault supported by naval gunfire, tanks and poison gas. It ended even more unsatisfactorily, and Dobell was relieved of command of Eastern Force on 19 April. His place was taken by Chetwode, while Chauvel took over the Desert Column, thereby becoming the first Australian to reach the rank of lieutenant general. Command of the Anzac Mounted Division passed to Chaytor. In June, during the Stalemate in Southern Palestine, General Sir Edmund Allenby took over the EEF from Murray. Allenby moved his headquarters to Palestine and re-organised his command along more regular lines. Eastern Force was abolished and two corps headquarters were formed, XX Corps under Chetwode and XXI Corps under Lieutenant General Edward Bulfin. The three corps commanders were professional soldiers, none of whom had graduated from a military college or a staff college, they had all been commissioned from the militia or volunteers.