Dionysius II of Syracuse
He was the son of Dionysius the Elder. When his father died in 367 BC, Dionysius began ruling under the supervision of his uncle, the philosopher Dion. Dion's disapproval of the young Dionysius's lavishly dissolute lifestyle compelled him to invite his teacher Plato to visit Syracuse. Together they attempted to restructure the government to be more moderate, with Dionysius as the archetypal philosopher-king.
Angered by the philosophers' attempt, Dionysius conspired with the historian Philistus and banished his uncle, taking complete power in 366 BC. Without Dion, Dionysius's rule became increasingly unpopular, as he was mostly incompetent in governing men and commanding soldiers. When Plato appealed for Dion's return, the irritated Dionysius interfered with Dion's property and finances and gave his wife to another man. Before this, Dion's Syracusan estates had financed his peaceful and comfortable life overseas in Athens, but Dionysius' last offence spurred him into action.
Dion formed a small army of 800 mercenaries at Zacynthus and returned to Sicily in 357 BC, much to the delight of the Syracusans. As Dionysius was in Caulonia, Italy at the time, Dion easily took all but Syracuse's island citadel. Dionysius sailed back to Syracuse immediately, and upon his return he attempted attacks from the citadel and tried to negotiate peace treaties. When he was unsuccessful in all attempts, he sailed away to Locri, Italy and left the citadel in the hands of his son Apollocrates.
In exile, Dionysius took advantage of the friendly citizens of Locri and became the city's tyrant, treating the locals with great cruelty. He did not return to Syracuse until 346 BC, eight years after Dion's assassination by his officers. Soon after he left Locri, the locals drove out the remaining troops and took their revenge on Dionysius's wife and daughters. Dionysius was able to regain power in Syracuse only because of its great political instability, as he was still very unpopular among the Syracusans. In the preceding several years, many other cities on Sicily had split from Syracuse and were ruled by local tyrants. Several of these cities joined the Syracusans in an attack against Dionysius which proved to be quite successful, and Dionysius was forced back into the citadel. At this time, 344 BC, Timoleon arrived and began his invasion of Sicily. Dionysius, out of respect for Timoleon and quite aware he no longer had a chance of victory, arranged the surrender of the citadel and was given safe passage to Corinth, Greece. For the next year until his death, Dionysius lived privately in Corinth in an increasingly miserable state.
In popular culture
Dionysius is one of the central characters in the legend of the Sword of Damocles.
Dionysius also appears in Dante's Inferno, in which he is referred to as "Dionysius of Sicily" in Canto 12. He is among the many souls named by Chiron that boil in blood for violence against others.