Iliero's brother Thrasybulus, whose accession took place in n.c. 467, was driven away for his tyranny by the people after one year's reign. An assembly was then convened, in which a new constitution was framed, the public offices being filled chiefly by the ancient citizens.
In the year n.e. 427 the people of Leontini, being hard pressed by the Svraeusane, applied to Athens for assistance. An Athenian fleet, with troops, was sent to Sicily, but after several desultory actions peace was made between Syracuse and Leontini, and the Athenian expedition withdrew. In ac. 416 a quarrel between the towns of Egesta and Sella's', brought in the Syracusans, who took the part of Selinns. The Egeetans and Leontiniana applied to Athens for aid. The Athenians declared war, and a formidable armament sailed for Sicily, n.c. 415. The Athenian expedition of 136 triremes, with a considerable land force, under Nicias, Alcibiades, and Lamachus, after sailing round Sicily, in quest of auxiliaries against Syracuse in vain, seized Catena, where they passed the winter. Meantime Alcibiades had been recalled, and the supreme command remained with Miele& The Syracusane sent envoys to Corinth to request assistance, and both Corinth and Sparta resolved to send succour to Syracuse under Gylippus, a celebrated Lacedemonian captain.
In the spring of n.e. 414 Nicias, having embarked his troops at Catena, landed a party of them in the bay of Thapsus, north of Syracuse, which took possession of the heights of Epipolx, and built there a fort which they called Labdalum. They then began to build a will from Port Trogilos to the Great Harbour, so as to inclose Syracuse on the land side, whilst their fleet blockaded it by sea. In the meantime Gylippus arriving, marched against Epipolas, seized the fort Labdalum, and annoyed the Athenians in their encampment. The Syracusans attacked the Athenian fleet at the entrance of the Great Harbour ; the fight was not decisive; but Gylippus with his land forces surprised the forts which the Athenians had raised on the peninsula of Plemmyrium. Another sea-fight took place, in which the Athenian galleys were worsted. Soon after Demosthenes and Eurymedon arrived from Athens with a new fleet of 73 galleys and about 8000 soldiers. Demosthenes attacked the heights of Epipolre by night, but was repulsed with great loss. After several discordant councils among the Athenian generals, it was resolved to embark the soldiers secretly and sail away with the fleet. The Syracusans having heard of this, attacked the Athenian fleet in the Great Harbour, and defeated it. Eurymedon was killed, and 18 Athenian galleys were taken. The Syracusans then blocked sip the entrance of the Great Harbour by means of galleys and other vessels, connecting them together with chains, and thus shut up the Athenians. Nicias then resolved to fight his way out with the fleet. The Athenian vessels were heavy, those of the Syracusaus light : the former, in trying to break through the chain, got crowded in one mass and became unmanageable; the crews were exposed to showers of stones from the enemy, the Athenian fleet was driven against the shore, and the greater part of it was taken or sunk. At last the Athenians resolved to abandon their remaining vessels and stores, their sick and wounded, and commenced their disastrous retreat. Of 40,000 men who had been engaged in the expedition, all were killed or taken prisoners, and not one of 200 vessels returned to Athens.
Of the prisoners all the freeborn Athenians and the Sicilians who were with them were confined in the quarries; the rest, servants, followers of the camp, &c., were sold as slaves. Nicias and Demos thenes were put to a cruel death. The prisoners in the quarries receiving but a small pittance of barley-bread and water, and having no shelter by day or night, diseases broke out among them. The bodies of the dead were left to putrefy among the living, and this created contagion, of which most of them perished. Thus ended this formidable expedition, the ill success of which broke down the power of Athens, and had a great influence on the result of the Pelopon nesian war.
After the defeat of the Athenians, Diodes proposed a law for the establishment of a democratic constitution in Syracuse, and compiled a criminal code of a very severe kind. This democratic constitution lasted very few years, for in p.c. 405 Dionysius was elected commander, and soon became tyrant of Syracuse. During the reign of this able and unscrupulous man, Syracuse reached the highest point of power and prosperity. Dionysius carried on long wars with the Carthaginians, whom he defeated and deprived of all their possessions in Sicily, n.c. 897. But the Carthaginians returned the following year, and after various successes laid siege to Syracuse by land and sea. A pestilence however broke out in their camp, and Dionysius taking advantage of the calamity, defeated the besieging forces and burnt great part of the fleet, whereupon the Carthaginians withdrew, but peace was not made till n.c. 392. Dionysius also conquered several of the Greek cities of southern Italy, and removed their inhabitants to Syracuse. For some years previous to his death, in n.c. 367, he was again engaged in wars with Carthage. lie was succeeded by his son Dionysius the younger, who was expelled by Timeleen. Tirnoleon established a government of mixed depmeracy and aristocracy. After Timeleon's death, B.C. 337, there was a period of twenty years marked by no very important events, till n.c. 317, when Agathocles, originally a potter, became autocrat of Syracuse. Agathocles was defeated by the Carthaginians at the battle of Himont, and immediately after closely besieged in Syracuse, from which sailing forth with a small force he carried war into the enemy's country, landing in Africa (August 15, 310 n.o.). He quitted Africa, where he was constantly victorious over the Carthaginians, B.O. 307, and returned to Sicily, which ho soon reduced to subjection. After the death of Agathoclea, n.c. 289, Syracuse recovered its independence, but being distracted by factions, the people chose, B.C. 275, for their praetor, Were, who was a descendant of king Gelon, and after five years more he was made king. He died n.c. 216. His son Hieronymus rashly quarrelled with Rome, and although he was murdered shortly after, his false policy was persevered in, and a Roman army, under Marceline, laid siege to Syracuse, and took it in n.c. 212. From that time Syracuse was merely a town of the Roman province of Sicily. After the downfal of the empire it was taken and plundered by the Saracens (May 21,-S.D. 878). Many ancient monuments were still remaining in 1693, when they were destroyed by an earthquake.
(Thucydidea, vi, vii. ; Diodorus, xiv., xvi., xix.; 11f filler, History of the Doric Race; Burigny, Histoire de Sicily; Clinton, Rani Helienici.)