The problem before him was anything but easy, for Halicarnassus, besides being strongly fortified, had through the presence of the Persian fleet free communication with the outside. It could be supplied with food, although the opportunity of obtaining mercenary troops from Greece was made difficult through the fear of Macedon. The city walls were surrounded with wide ditches and these Alexander filled up, in order to give access to his siege engines. Several breaches were made, but the first attempt to storm the place failed, and the defenders of the city erected new fortifications in place of those that had been cut down. They also made a sortie, trying to destroy the siege engines, but were repulsed with loss. Memnon saw that the town could no longer be held, and by night embarked his troops, carrying them to Cos; but before he left he set fire to the abandoned town. Alexander immediately entered, showed himself merciful to its citizens, and proceeded on his march, leaving a division of 3050 men to watch the citadel of Halicarnassus, which evidently he did not think of sufficient importance to besiege now that the Persians had only a small number of troops in the neighborhood, in Salmakis and on the island Arconnesus. The whole of the province of Caria now ceased to resist, with the exception of a few places on the coast. A part of the Greek army, under the orders of Parmenio, were sent into winter quarters in Lydia, while Alexander advanced through Lycia and Pamphylia, without meeting any real resistance, and marched by the way of the mountainous country of Pisidia, among a population never conquered by the Persians, and in the spring of 333 joined Parmenio at Gordion, the ancient capital of Phrygia. From here the route of the army was through Cappadocia by the narrow pass called the Cilician Gate, by which the road from the interior plateau crosses the Taurus on its way to Tarsus. The garrison which occupied the pass fled on the approach of the Greek army, Tarsus itself was abandoned, and the whole province of Cilicia was occupied without resistance.