Little has been written about him during the subsequent campaigns of Alexander, however he appears to have earned a reputation as an able soldier. In the division of the provinces after Alexander the Great's death, Neoptolemus obtained the government of Armenia, 323 BC. However, as he had a reputation of being restless and unsettled, Perdiccas regarded him with suspicion. So in 321 BC, when the Perdiccas set out for Ptolemaic Egypt, he placed Neoptolemus under the command of Eumenes, who was told to exercise particular vigilance regarding Neoptolemus .
Perdiccas' suspicions turned out to be well founded: Neoptolemus immediately entered into correspondence with the hostile Macedonian leaders, Antipater and Craterus, and, on being ordered by Eumenes to join him with his contingent, refused to comply. In response, Eumenes immediately marched against him, defeated his army, and compelled all the Macedonian troops in his service to take the oath of fidelity to Perdiccas.
Neoptolemus managed to escape with a small body of cavalry and joined Craterus, whom he persuaded to march immediately against Eumenes, while the latter was still celebrating his victory and unprepared for a fresh attack. But their cautious adversary was not taken by surprise and met his enemies in a pitched battle. During this battle, Neoptolemus commanded the left wing, on which he was opposed to Eumenes himself; and the two leaders, who were bitter personal enemies, sought each other out during the battle and engaged in single combat, in which, after a desperate struggle, Neoptolemus was slain by Eumenes.
- Smith, William (editor); Dictionary of Greek and Roman Biography and Mythology, "Neoptolemus (1)", Boston, (1867)
This article incorporates text from a publication now in the public domain: Smith, William, ed. (1870). "article name needed". Dictionary of Greek and Roman Biography and Mythology.