[2][3] He first governed as guardian (epitropos)[a] for his young nephew Orestes when Archelaus died in 400/399 BC.

However, Diodorus reports that Aeropus murdered Orestes three years later, but it is also possible that he had simply won the support of the Macedonian nobility.

[7] Two traditions relate how Aeropus was overawed by either the insolence[8][9] or the stratagems[10] of the Lacedaemonian king Agesilaus, allowing his armies free passage through Macedonia after their campaign in Asia.

There is a minority view among scholars that Aeropus was a Lyncestian prince, rather than an Argead, who married into the dynasty, therefore enabling him later to become regent for Orestes.

[11] However, the majority of historians believe Aeropus to have been Perdiccas' son and thus a member of the dynasty.