(Ἱέρων). (1) A Sicilian who succeeded his brother Gelon as tyrant of Syracuse, B.C. 478. He committed many acts of violence, encouraged spies, and kept a mercenary guard around his person. He was ambitious of extending his dominion, and his attempts proved successful. After the death of Theron of Agrigentum, Hiero defeated his son Thrasydaeus, who was soon afterwards expelled by his countrymen. He took Naxus and Catana, and, having driven away the inhabitants from both towns, replaced them by Syracusan and Peloponnesian colonists. He changed the name of Catana to Aetna, and he himself assumed the title of Aetnaeus (Αἰτναῖος). Having joined his fleet to that of the people of Cumae, he succeeded in clearing the Tyrrhenian Sea of the Etruscan and other pirates who infested it. His chariots repeatedly won the prize at the Olympic Games, and his success on those occasions formed the theme of several of the odes of Pindar, who was his guest and friend. Aeschylus, Simonides, Bacchylides, and Epicharmus were also well received at the court of Hiero, who was fond of the society of learned men. His intimacy with Simonides is the subject of Xenophon's dialogue entitled Ἱέρων. Hiero died at Catana, B.C. 467, and was succeeded by his brother Thrasybulus, who had all his faults without any of his good qualities, and was at last driven away by the Syracusans, who restored the government to the commonwealth ( Diod. Sic.xi. 48 foll.).
(2) The second of the name, son of Hierocles, a wealthy citizen of Syracuse, and a descendant of Gelon, distinguished himself in early life by his brilliant qualities, and served with distinction also under Pyrrhus in his Sicilian campaigns. After Pyrrhus had suddenly abandoned Sicily, the Syracusans found themselves threatened on one side by the Carthaginians and on the other by the Mamertines, a band of Campanian mercenaries, who had treacherously taken possession of Messana. The Syracusan troops, being in want of a trusty leader, chose Hiero by acclamation, and the Senate and citizens, after some demur, ratified the choice, B.C. 275. After various successful operations against the Mamertines, Hiero returned to Syracuse, where, through the influence of Leptines, his father-in-law, a leading man among the aristocratic party, he was proclaimed king, B.C. 270. Shortly afterwards the Mamertines at Messana quarrelled with the Carthaginians, who had managed to introduce a garrison into the citadel, and drove them out, upon which the Carthaginians invited Hiero to join his forces to theirs, in order to drive the Mamertines out of Sicily. Hiero having assented, encamped under the walls of Messana on one side, and the Carthaginians fixed their camp on the other, while their squadron guarded the strait. The Mamertines, meanwhile, had applied to the Romans for assistance, claiming a common origin with them, as being descended from Mars, called Mamers in the Oscan language; and Rome eagerly seized this opportunity of obtaining a footing in Sicily. The consul Appius Claudius marched to Rhegium, and, having contrived to pass the strait in the night unobserved by the Carthaginian cruisers, he surprised Hiero's camp, routed the soldiers, and obliged the monarch himself to seek safety in flight. The consul next attacked the Carthaginian camp with the same success, and this was the beginning of the First Punic War, B.C. 265. In the following year the Romans took Tauromenium and Catana and advanced to the walls of Syracuse, when Hiero sued for peace, which he obtained on condition of paying 100 talents of silver and supplying the Roman army with provisions. He punctually fulfilled his engagements, remaining faithful to Rome during the whole of the war, and by his supplies was of great service to the Roman armies, especially during the long sieges of Agrigentum and Lilybaeum. Hiero was included in the peace between Rome and Carthage, by which his territories were [figure in text: Coin of Hiero II.] secured to him, and he remained in friendship with both States. He even assisted Carthage at a very critical moment by sending her supplies of provisions during the war which she had to sustain against her mercenaries. The period of peace which elapsed between the end of the First and the beginning of the Second Punic Wars, from B.C. 241 to 218, was most glorious for Hiero and most prosperous for Syracuse. Commerce and agriculture flourished, and wealth and population increased to an extraordinary degree. Hiero paid particular attention to the administration of the finances, and made wise regulations for the collection of the tithe or tax on land, which remained in force throughout Sicily long after his time, and are mentioned with praise by Cicero as the lex Hieronica. Hiero introduced the custom of farming out the tax every year by auction. He embellished and strengthened Syracuse, and built large ships. Archimedes lived under Hiero's reign. When the Second Punic War broke out, Hiero continued true to his Roman alliance, and, after the Trasimenian defeat, he sent a fleet to Ostia with provisions and other gifts, and a body of light troops to the assistance of Rome. He lived to see the battle of Cannae, after which his son Gelon embraced the part of the Carthaginians. Gelon, however, died, not without suspicion of violence, and Hiero himself, being past ninety years of age, ended his days soon afterwards (B.C. 216), leaving the crown to his grandson, Hieronymus.