A change in History

[Maion Maroneios]

If the family of Pyrrhos conquered and solidified their power in Makedonia, they would call themselves the kings of Makedonia. Just calling them "Makedonia" would probably work. You could call old Makedonia "Pergamon"...

I highly doubt that. The Epeirotai might have been Hellenes, but they were different from the Makedones. Even when Pyrrhos claimed the throne of Makedonia, he didn't call his Kingdom as such. His goal was simply to unify Hellas under his Crown and re-take (probably, I might be wrong here) the Empire of Megas Alexandros. In any way, he [Pyrrhos] was very ambitious and would have carved himself a pretty nice Kingdom, had he not died that day in Argos.

I have another option for a name, once a faction unifies Hellas. You could go for "Symmachia Hellenon" (ΣΥΜΜΑΧΙΑ ΕΛΛΗΝΩΝ in Greek), or "Alliance of the Greeks", since even Philippos (Alexandros' father) called the unified front against the Medes "Corinthian League". But that would probably take some years after the original conquest, since turning from a rulilng tribe (like the Molossoi) to masters of a nation and giving your subjects a sense of unity, would probably require time for the integration of the various attributes of each conquered people into the new Kingdom.

Maion