On the 19th Calleja attacked the town, but was forced to retreat. He then regularly besieged the place and its insurgent visitors for more than two months and a half. In this period, the troops on both sides were not unoccupied. Various skirmishes took place, but without signal results of importance to either party. Morelos strove to prolong the siege until the rainy season set in, when he felt confident that Calleja would be forced to withdraw his troops, who could not endure the combined heat and moisture of the _tierra caliente_ during the summer months. Calleja, on the other hand, supposed that by sealing the town hermetically, and cutting off all supplies, its inhabitants and troops would soon be forced to surrender. Nor did he act unwisely for the success of his master. Famine prevailed in the besieged garrison. Corn was almost the only food. A cat sold for six dollars, a lizard for two, and rats and other vermin for one. But Morelos still continued firm, hoping by procrastination and endurance, to preserve the constancy of his men until the month of June, when the country is generally deluged with rain and rendered insalubrious to all who dwell habitually in colder regions, or are unacclimated in the lower vallies and table lands of Mexico. His hopes, however, were not destined to be realized, for, upon consultation, it was found absolutely necessary to risk a general engagement or to abandon the town. The general engagement was considered injudicious in the present condition of his troops, so that no alternative remained but that of retreat. This was safely effected on the night of the 2d of May, 1812, notwithstanding the whole army of the insurgents was obliged to pass between the enemy's batteries. After quitting the town, the forces were ordered to disperse, so as to avoid forming any concentrated point of attack for the pursuing Spaniards, and to reunite as soon as possible at Izucar, which was held by Don Miguel Bravo. Calleja entered the abandoned town cautiously after the departure of the besieged, but the cruel revenge he took on the innocent inhabitants and harmless edifices, is indelibly imprinted in Mexican history as one of the darkest stains on the character of a soldier, whose memory deserves the execration of civilized men.