He was the maternal grandfather of Alexander the Great and great-grandfather of Pyrrhus of Epirus.
[2] This was also a name of the son of the warrior Achilles and the Princess Deidamia in Greek mythology, and also the mythical progenitor of the ruling dynasty of the Molossians of ancient Epirus.
On the death of Alcetas, Neoptolemus and his brother Arybbas agreed to divide the kingdom, and continued to rule their respective portions without any interruption of the harmony between them, until the death of Neoptolemus, which, according to German historian Johann Gustav Droysen, may be placed about 360 BC.
The first epigraphical evidence of the Molossian League goes back to 370 BC under Neoptolemus.
Dictionary of Greek and Roman Biography and Mythology.