1911 Encyclopædia Britannica/Gallus, Gaius Aelius
GALLUS, GAIUS AELIUS, praefect of Egypt 26–24 B.C. By order of Augustus he undertook an expedition to Arabia Felix, with disastrous results. The troops suffered greatly from disease, heat, want of water and the obstinate resistance of the inhabitants. The treachery of a foreign guide also added to his difficulties. After six months Gallus was obliged to return to Alexandria, having lost the greater part of his force. He was a friend of the geographer Strabo, who gives an account of the expedition (xvi. pp. 780-782; see also Dio Cassius liii. 29; Pliny, Nat. Hist. vi. 32; C. Merivale, Hist. of the Romans under the Empire, ch. 34; H. Krüger, Der Feldzug des A. G. nach dem glücklichen Arabien, 1862). He has been identified with the Aelius Gallus frequently quoted by Galen, whose remedies are stated to have been used with success in an Arabian expedition.