One line of walls soon fell beneath the rams of the besiegers, but it only revealed another within. The Christians dragged vessels overland from Civitat (the modern Guemlik), and by night launched them upon the Lake of Ascanius, thus cutting off reinforcement for the garrison within the city. After seven weeks of almost incredible effort, Nicæa was about to fall to the reward of its Latin conquerors, when suddenly there appeared upon the ramparts numerous strange standards. To the amazement of the Christians, these proved to be not those of the Turk, but of the Greek. Alexius, conniving with the enemy, had surreptitiously introduced into Nicæa a detachment of his own troops, and thus secured the surrender to himself of what had been won by others. The rage of the crusaders knew no bounds. With the price of their blood they had gained nothing but the honor of their valor. Only the utmost discretion on the part of the chieftains prevented the army from declaring war upon Alexius and marching back to the capture of Constantinople. It afterwards transpired that Alexius’s movement had been encouraged by some of the leaders of the crusade, that their armies might not be weakened by leaving garrisons to hold the captured places. CHAPTER XIII. BATTLE OF DORYLÆUM—TARSUS—DEFECTION OF BALDWIN. From Nicæa the Christians advanced (June 29, 1097) through Asia Minor towards the Holy Land. Their march was over a roadless country, threading the ravines and climbing the precipices of mountains, across plains desolated by the retreating foe, under the burning heat of the midsummer sun, and exposed to the guerilla attacks of a half-beaten enemy, whose main army was rapidly recruiting and waiting with double its former numbers to renew the battle.