Helenus, (gr. Helenos), son of Pyrrhus, king of Epeirus, by Lanassa, daughter of Agathocles. He was very young when he accompanied his father on his expedition to Italy, B. C. 280; but Pyrrhus is said to have conceived the project, when elated with his first successes in Sicily, of establishing Helenus there as king of the island, to which as grandson of Agathocles he appeared to have a sort of hereditary claim. (Just. xviii, 1, xxiii. 3.) But the tide of fortune soon turned; and when Pyrrhus saw himself compelled to abandon both Sicily and Italy, he left Helenus at Tarentum, together with Milo, to command the garrison of that city, the place in Italy of which he still retained possession. It was not long before he recalled them both from thence, in consequence of the unexpected views that had opened to his ambition in Macedonia and Greece. Helenus accompanied his father on his expedition into the Peloponnese (272 BC), and after the fatal night attack on Argos, in which Pyrrhus himself perished, he fell into the hands of Antigonus Gonatas, who however behaved towards him in the most magnanimous manner, treated him with the utmost distinction, and sent him back in safety to Epeirus, bearing with him the remains of his father. (Just. xxv. 3, 5; Plut. Pyrrhs. 33, 34.) After this we hear no more of him.