The fortress of Euryalus, which, situated at the extreme western end of the suburbs, protected these and the principal road leading from the interior to Syracuse, was thus cut off and fell not long afterwards.
When the siege of the city thus began to assume a turn favourable to the Romans, the two armies under Himilco and Hippocrates advanced to its relief, and attempted a simultaneous attack on the Roman positions, combined with an attempt at landing on the part of the Carthaginian fleet and a sally of the Syracusan garrison; but the attack was repulsed on all sides, and the two relieving armies were obliged to content themselves with encamping before the city, in the low marshy grounds along the Anapus, which in the height of summer and autumn engender pestilences fatal to those that tarry in them.

These pestilences had often saved the city, oftener even than the valour of its citizens; in the times of the first Dionysius, two Phoenician armies in the act of besieging the city had been in this way destroyed under its very walls.

Now fate turned the special defence of the city into the means of its destruction; while the army of Marcellus quartered in the suburbs suffered but little, fevers desolated the Phoenician and Syracusan bivouacs.

Hippocrates died; Himilco and most of the Africans died also; the survivors of the two armies, mostly native Siceli, dispersed into the neighbouring cities.

The Carthaginians made a further attempt to save the city from the sea side; but the admiral Bomilcar withdrew, when the Roman fleet offered him battle.