The First Transjordan attack on Amman and to their enemy as the First Battle of the Jordan took place between 21 March and 2 April 1918, as a consequence of the successful Battle of Tell 'Asur which occurred after the Capture of Jericho in February and the Occupation of the Jordan Valley began, during the Sinai and Palestine Campaign of World War I. During the First Transjordan attack large incursions into Ottoman territory occurred. Firstly the Passage of the Jordan River, was successfully captured between 21 and 23 March, followed by the first occupation of Es Salt in the hills of Moab between 24 and 25 March. The First Battle of Amman took place between 27 and 31 March when the Anzac Mounted Division and the Imperial Camel Corps Brigade were reinforced by two battalions of 181st Brigade followed by a second two battalions from the 180th Brigade and artillery. The Fourth Army headquarters located in Amman was strongly garrisoned and during the battle received reinforcements on the Hejaz railway, the strength of which eventually forced the attacking force to retire back to the Jordan Valley between 31 March and 2 April. The Jordan Valley would continue to be occupied by the Egyptian Expeditionary Force (EEF) through the summer until the middle of September 1918 when the Battle of Megiddo began.