(Μάμερκος), tyrant of Catana, at the time when Timoleon landed in Sicily, B. C. 344. He is termed by Plutarch a man both warlike and wealthy. After the defeat of Hicetas at Adranum by Timoleon, Mamercus joined the latter and concluded a treaty of alliance with him. But when Timoleon had not only made himself master of Syracuse, but defeated the Carthaginians in the great battle of the Crimissus (B. C. 339), Mamercus became apprehensive that his object was nothing less than the complete expulsion of all the tyrants from Sicily, and in consequence concluded a league with Hicetas and the Carthaginians to oppose his progress. They at first obtained a partial success, and cut to pieces a body of mercenaries in the Syracusan service; but Hicetas was defeated by Timoleon, and soon after fell into his hands; after which the Corinthian leader marched against Catana. Mamercus met him in the field, but was defeated with heavy loss, and the Carthaginians now concluded a peace with Timoleon. Thus abandoned by his allies Mamercus despaired of success, and fled to Messana, where he took refuge with Hippon, tyrant of that city. Tinoleon, however, quickly followed, and laid siege to Messana both by sea and land, whereupon Hippon took to flight, and Mamercus surrendered to the Corinthian general, stipulating only for a regular trial before the Syracusans. But as soon as he was brought into the assembly of the people there, he was condemned by acclamation, and executed like a common malefactor. (Plut. Tim. 13, 30, 31, 34; Diod. 16.69, 82 ; Corn. Nep. Timol. 2.) We may, perhaps, infer from an expression of Cornelius Nepos, that Mantercus was not a Sicilian by birth, but had first come to the island as a leader of Italian mercenaries. Plutarch informs us (Timol. 31) that he prided himself much upon his skill in poetry, apparently with but little reason, if we may judge from the two verses preserved to us by that author.