considerable force of infantry who were called Shield-bearers: they were not so heavily armed as the phalangites, or as was the case with the Greek regular infantry in general, but they were equipped for close fight, as well as for skirmishing; and were far superior to the ordinary irregular troops of Greek warfare. They were about six thousand strong. Besides these he had several bodies of Greek regular infantry; and he had archers, slingers, and javelin-men, who fought also with broadsword and target, and who were principally supplied him by the highlanders of Illyria and Thracia. The main strength of his cavalry consisted in two chosen regiments of cuirassiers, one Macedonian, and one Thessalian, each of which was about fifteen hundred strong. They were provided with long lances and heavy swords, and horse as well as man was fully equipped with defensive armour. Other regiments of regular cavalry were less heavily armed, and there were several bodies of light horsemen, whom Alexander's conquests in Egypt and Syria bad enabled him to mount superbly.
A little before the end of August, Alexander crossed the Euphrates at Thapsacus, a small corps of Persian cavalry under Mazæus retiring before him. Alexander was too prudent to march down through the Mesopotamian deserts, and continued-