On this day he shut them up in the city, and encamping near the wall, he resolved to intercept them by a circumvallation; but on the next day Glaucias, king of the Taulantians, arrived with a great force. Then, indeed, Alexander gave up the hope of capturing the city with his present force, since many warlike troops had fled for refuge into it, and Glaucias with his large army would be likely to follow him up closely if he assailed the wall. But he sent Philotas on a foraging expedition, with the beasts of burden from the camp and a sufficient body of cavalry to serve as a guard. When Glaucias heard of the expedition of Philotas he marched out to meet him, and seized the mountains which surrounded the plain, from which Philotas intended to procure forage. As soon as Alexander was informed that his cavalry and beasts of burden would be in danger if night overtook them, taking the shield-bearing troops,[61] the archers, the Agrianians, and about four hundred cavalry, he went with all speed to their aid. The rest of the army he left behind near the city, to prevent the citizens from hastening forth to form a junction with Glaucias (as they would have done), if all the Macedonian army had withdrawn. Directly Glaucias perceived that Alexander was advancing, he evacuated the mountains, and Philotas and his forces returned to the camp in safety. But Clitus and Glaucias still imagined that they had caught Alexander in a disadvantageous position; for they were occupying the mountains, which commanded the plain by their height, with a large body of cavalry, javelin-throwers, and slingers, besides a considerable number of heavy-armed infantry. Moreover, the men who had been beleaguered in the city were expected to pursue the Macedonians closely if they made a retreat. The ground also through which Alexander had to march was evidently narrow and covered with wood; on one side it was hemmed in by a river, and on the other there was a very lofty and craggy mountain, so that there would not be room for the army to pass, even if only four shield-bearers marched abreast. CHAPTER VI. DEFEAT OF CLITUS AND GLAUCIAS.