The Romans had thus gained their immediate object. By their double alliance with Messana and Syracuse, and the firm hold which they had on the whole east coast, they secured the means of landing on the island and of maintaining--which hitherto had been a very difficult matter--their armies there; and the war, which had previously been doubtful and hazardous, lost in a great measure its character of risk. Accordingly, no greater exertions were made for it than for the wars in Samnium and Etruria; the two legions which were sent over to the island for the next year (492) sufficed, in concert with the Sicilian Greeks, to drive the Carthaginians everywhere into their fortresses. The commander-in-chief of the Carthaginians, Hannibal son of Gisgo, threw himself with the flower of his troops into Agrigentum, to defend to the last that most important of the Carthaginian inland cities. Unable to storm a city so strong, the Romans blockaded it with entrenched lines and a double camp; the besieged, who numbered 50,000 soon suffered from want of provisions. To raise the siege the Carthaginian admiral Hanno landed at Heraclea, and cut off in turn the supplies from the Roman besieging force. On both sides the distress was great. At length a battle was resolved on, to put an end to the state of embarrassment and uncertainty. In this battle the Numidian cavalry showed itself just as superior to the Roman horse as the Roman infantry was superior to the Phoenician foot; the infantry decided the victory, but the losses even of the Romans were very considerable. The result of the successful struggle was somewhat marred by the circumstance that, after the battle, during the confusion and fatigue of the conquerors, the beleaguered army succeeded in escaping from the city and in reaching the fleet. The victory was nevertheless of importance; Agrigentum fell into the hands of the Romans, and thus the whole island was in their power, with the exception of the maritime fortresses, in which the Carthaginian general Hamilcar, Hanno's successor in command, entrenched himself to the teeth, and was not to be driven out either by force or by famine. The war was thenceforth continued only by sallies of the Carthaginians from the Sicilian fortresses and their descents on the Italian coasts. Beginning of the Maritime War The Romans Build a Fleet