Agrigentum was built on a site naturally strong and had been skilfully fortified. It occupied a group, or rather part of a group, of hills which on all sides but one, the south-western, rose precipitously from the plain, so precipitously indeed that attack was impossible. On the north-east, crowning the height of the most lofty hill, was the citadel, approachable by one narrow path only. While the fortifications were strong and well cared for, they were also adequately garrisoned. Besides a numerous force raised from her own citizens Agrigentum had in her pay eight hundred Campanian mercenaries, who three years before had served under Hannibal, and had thrown up their engagement dissatisfied with their pay. She had also secured the services of fifteen hundred other mercenaries who were under the command of Dexippus, a Spartan soldier of fortune. The citizens were confident in their ability to repel any attack that might be made on them. When Hannibal proposed a treaty of alliance, which, however, would permit Agrigentum to stand neutral in the approaching conflict, it was promptly rejected. For a while all went well with the defence. Hannibal assaulted the town at the only point where an assault was possible, but accomplished nothing. He even lost his siege train, for the Agrigentines made a sally, captured, and burnt it. He then adopted the alternative plan of constructing a mound which would put the assailants on a level with the walls. The cemetery of Agrigentum was situated outside the walls in the same quarter as that which was the scene of the attack. Indeed, it was only here that there was any level space. Massive tombs of stone, in which reposed the remains of distinguished or wealthy Agrigentines of past days, abounded, and Hannibal, with the national carelessness of all religions other than his own, determined to make use of these materials for his siege work. His workmen had destroyed many of the tombs, and were busy with the most splendid of them all, that of Theron (tyrant of Agrigentum from 488 to 472) when a thunderbolt fell on the spot. This was regarded by the Carthaginians as a manifest token of the divine displeasure. The panic which followed largely increased the fatalities from a disease which now appeared in the camp. Thousands perished, Hannibal himself being one of the victims. It was not till various expiations, one of them a human sacrifice, had been made that Himilco, who now succeeded to the chief command, was able to resume the operations of the siege.