HIERO H  ., tyrant of Syracuse from 270 to 216 B.C., was the illegitimate son of a Syracusan noble, Hierocles, who claimed descent from Gelo . On the departure of Pyrrhus from Sicily (275) the Syracusan army and citizens appointed him commander of the troops . He materially strengthened his position by marrying the daughter of Leptines, the leading citizen . In the meantime, the Mamertines, a body of Campanian mercenaries who had been employed by Agathocles, had seized the strong-hold of Messana, whence they harassed the Syracusans . They were finally defeated in a pitched battle near Mylae by Hiero, who was only prevented from capturing Messana by Carthaginian interference . His grateful countrymen then chose him king (270) . In 264 he again returned to the attack, and the Mamertines called in the aid of Rome . Hiero at once joined the Punic leader Hanno, who had recently landed in Sicily; but being defeated by the consul Appius Claudius, he withdrew to Syracuse . Pressed by the Roman forces, in 263 he was compelled to conclude a treaty with Rome, by which he was to rule over the south-east of Sicily and the eastern coast as far as Tauromenium (Polybius i . 8-16; Zonaras viii . 9) . From this time till his death in 216 he remained loyal to the Romans, and frequently assisted them with men and provisions during the Punic wars (Livy xxi .

49-51, xxii . 37,

xxiii . 21) . He kept up a powerful fleet for defensive purposes, and employed his famous kinsman Archimedes in the construction of those engines that, at a later date, played so important a part during the siege of Syracuse by the Romans . A picture of the prosperity of Syracuse during his rule is given in the sixteenth idyll of Theocritus, his favourite poet . See Diod . Sic. xxii . 24-xxvi . 24; Polybius i . 8-vii . 7; Justin xxiii . 4 .