Middle East Command was established in Cairo, during June 1939, due to the rising tensions in Europe. Its purpose was to provide a centralised command structure in times of war for the three separate army commands based within the Mediterranean and Middle East areas: Egypt, Sudan and Palestine/Transjordan. During periods of peace the command exerted authority over land forces based within Egypt, the Sudan, Palestine, Transjordan, and Cyprus. However, if war broke out, the Command's area of responsibility would be extended to include British Somaliland, Aden, Iraq and the shores of the Persian Gulf. As the war progressed, Middle East Command authority was extended over further areas including Ethiopia, Eritrea, Libya and Greece. Lieutenant-General Sir Archibald Wavell, commanding officer of Southern Command in the United Kingdom, was chosen as the first General Officer Commanding in Chief, a position he took up in July 1939, and was given the acting rank of General.