The affairs of the Sicilian Greeks, an important branch of the Hellenic race, deserve a passing notice. A few years after the destruction of the Athenian armament, Dionysius made himself master of Syracuse, and openly seized upon the supreme power (B.C. 405). His reign as tyrant or despot was long and prosperous. After conquering the Carthaginians, who more than once invaded Sicily, he extended his dominion over a great part of the island, and over a considerable portion of Magna Graecia. He raised Syracuse to be one of the chief Grecian states, second in influence, if indeed second, to Sparta alone. Under his sway Syracuse was strengthened and embellished with new fortifications, docks, arsenals, and other public buildings, and became superior even to Athens in extent and population.

Dionysius was a warm patron of literature, and was anxious to gain distinction by his literary compositions. In the midst of his political and military cares he devoted himself assiduously to poetry, and not only caused his poems to be publicly recited at the Olympic games, but repeatedly contended for the prize of tragedy at Athens. In accordance with the same spirit we find him seeking the society of men distinguished in literature and philosophy. Plato, who visited Sicily about the year 389 from a curiosity to see Mount AEtna, was introduced to Dionysius by Dion. The high moral tone of Plato's conversation did not however prove so attractive to Dionysius as it had done to Dion; and the philosopher was not only dismissed with aversion and dislike, but even, it seems through the machinations of Dionysius, seized, bound, and sold for a slave in the island of AEgina. He was, however, repurchased by Anniceris of Cyrene, and sent back to Athens.

Dionysius died in B.C. 367, and was succeeded by his eldest son, commonly called the younger Dionysius, who was about 25 years of age at the time of his father's death. At first he listened to the counsels of Dion, who had always enjoyed the respect and confidence of his father. At the advice of Dion he invited Plato to Syracuse, where the philosopher was received with the greatest honour. His illustrious pupil immediately began to take lessons in geometry; superfluous dishes disappeared from the royal table; and Dionysius even betrayed some symptoms of a wish to mitigate the former rigours of the despotism. But now the old courtiers took the alarm. It was whispered to Dionysius that the whole was a deep-laid scheme on the part of Dion for the purpose of effecting a revolution and placing his own nephews on the throne. [The elder Dionysius had married two wives at the same time: one of these was a Locrian woman named Doris; the other, Aristomache, was a Syracusan, and the sister of Dion. The younger Dionysius was his elder son by Doris; but he also had children by Aristomache.] These accusations had the desired effect on the mind of Dionysius, who shortly afterwards expelled Dion from Sicily. Plato with difficulty obtained permission to return to Greece (B.C. 366). Dionysius now gave way to his vices without restraint, and became an object of contempt to the Syracusans. Dion saw that the time had come for avenging his own wrongs as well as those of his country. Collecting a small force, he sailed to Sicily, and suddenly appeared before the gates of Syracuse during the absence of Dionysius on an expedition to the coasts of Italy. The inhabitants, filled with joy, welcomed Dion as their deliverer: and Dionysius on his return from Italy found himself compelled to quit Syracuse (B.C. 356), leaving Dion undisputed master of the city. The latter was now in a condition to carry out all those exalted notions of political life which he had sought to instil into the mind of Dionysius. He seems to have contemplated some political changes; but his immediate and practical acts were tyrannical, and were rendered still more unpopular by his overbearing manners. His unpopularity continued to increase, till at length one of his bosom friends - the Athenian Callippus - seized the opportunity to mount to power by his murder, and caused him to be assassinated in his own house. This event took place in 353, about three years after the expulsion of the Dionysian dynasty. Callippus contrived to retain the sovereign power only a twelvemonth. A period of anarchy followed, during which Dionysius made himself master of the city by treachery, about B.C. 346. Dionysius, however, was not able to re-establish himself firmly in his former power. Most of the other cities of Sicily had shaken off the yoke of Syracuse, and were governed by petty despots. Meantime the Carthaginians prepared to take advantage of the distracted condition of Sicily. In the extremity of their sufferings, several of the Syracusan exiles appealed for aid to Corinth, their mother-city. The application was granted, and Timoleon was appointed to command an expedition destined for the relief of Syracuse.

Timoleon was distinguished for gentleness as well as for courage, but towards traitors and despots his hatred was intense. He had once saved the life of his elder brother Timophanes in battle at the imminent peril of his own; but when Timophanes, availing himself of his situation as commander of the garrison in the Acrocorinthus, endeavoured to enslave his country, Timoleon did not hesitate to consent to his death. Twice before had Timoleon pleaded with his brother, beseeching him not to destroy the liberties of his country; but when Timophanes turned a deaf ear to those appeals, Timoleon connived at the action of his friends, who put him to death, whilst he himself, bathed in a flood of tears, stood a little way aloof. The great body of the citizens regarded the conduct of Timoleon with love and admiration. In the mind of Timoleon, however, their approving verdict was far more than outweighed by the reproaches and execrations of his mother. For many years nothing could prevail upon him to return to public life. He buried, himself in the country far from the haunts of men, till a chance voice in the Corinthian assembly nominated him as the leader of the expedition against Dionysius.

Roused by the nature of the cause, and the exhortations of his friends, Timoleon accepted the post thus offered to him. His success exceeded his hopes. As soon as he appeared before Syracuse, Dionysius, who appears to have abandoned all hope of ultimate success, surrendered the citadel into his hands, on condition of being allowed to depart in safety to Corinth (B.C. 343). Dionysius passed the remainder of his life at Corinth, where he is said to have displayed some remnants of his former luxury by the fastidious taste which he showed in the choice of his viands, unguents, dress, and furniture; whilst his literary inclinations manifested themselves in teaching the public singers and actors, and in opening a school for boys.

Timoleon also expelled the other tyrants from the Sicilian cities, and gained a great victory over the Carthaginians at the river Crimesus (or Crimissus). He restored a republican constitution to Syracuse; and his first public act was to destroy the impregnable fortifications of the citadel of Ortygia, the stronghold of the elder and the younger Dionysius. All the rewards which Timoleon received for his great services were a house in Syracuse, and some landed property in the neighbourhood of the city. He now sent for his family from Corinth, and became a Syracusan citizen. He continued, however, to retain, though in a private station, the greatest influence in the state. During the latter part of his life, though he was totally deprived of sight, yet, when important affairs were discussed in the assembly, it was customary to send for Timoleon, who was drawn in a car into the middle of the theatre amid the shouts and affectionate greetings of the assembled citizens. When the tumult of his reception had subsided he listened patiently to the debate. The opinion which he pronounced was usually ratified by the vote of the assembly; and he then left the theatre amidst the same cheers which had greeted his arrival. In this happy and honoured condition he breathed his last in B.C. 336, a few years after the battle of Crimesus. He was splendidly interred at the public cost, whilst the tears of the whole Syracusan population followed him to the grave.