7. Brother of Gelon, tyrant of Syracuse. On the death of Hieron, Thrasybulus succeeded him in the government. It does not appear distinctly whether he assumed the tyranny because the son of Gelon was not yet old enough, or, as the language of Aristotle (Aristot. Pol. 5.8) indicates, though called tyrant, and possessing the substance of power, was in fact little more than the minister or favourite of his nephew, whom he is said to have corrupted, that he might afterwards supplant him. Aristotle's version of the matter also represents the resistance offered by the friends of the rightful heir, as leading to the overthrow of the dynasty. It is possible enough, as Dr. Thirlwall suggests Hist. of Greece, vol. iii. p. 224), that Thrasybulus became the guardian of his nephew on the death of Polyzelus, and before the death of Hieron; and that, having rendered the youth odious and contemptible, he found no difficulty, when Hieron died, in setting him aside, and usurping his authority. This supposition, however, still leaves unexplained Aristotle's statement about the expulsion of the dynasty, which is one of the most important features of his account. Little, therefore, is gained by any endeavour to reconcile the two versions. According to the more detailed narration of Diodorus (11.67), Thrasybulus directly succeeded Hieron, and soon provoked a revolt by his rapacity and cruelty. With the aid of foreign mercenaries, and some troops from Aetna and Catana, amounting altogether to 15,000 men, he maintained his ground for some time in Acradina and the Island. The Syracusans entrenched themselves in the quarter called Tyche, and sent for assistance to Gela, Agrigentum, Selinus, Himera, and the inland cities of Sicily. They readily lent their aid, and Thrasybulus was decisively defeated both by sea and by land. He thereupon entered into a negotiation with his revolted subjects, and was allowed to abdicate his authority and retire into exile. He withdrew to Locri, in Italy, and there ended his days. His dynasty ended with him.
A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890