The Most Succesfull Succesor

[bobbin]

But what real power did the Seleucids hold outside of Syria and Mesapotamia? They got smacked around practically everywhere until Antiochus showed up.

You should really read up on the actual history of the Seleukid Empire before making a statement like that. Sure they suffered there fair share of beatings but they also doled them out just as often, and they were the only successor who were able to repeatedly recover from major defeats.

The Ptolemies while starting out strong and even expanding their empire a little, entered a long slow decline, gradually losing territories to the Seleukids and Makedones before their final swift conquest by the Romans.

The Makedones (if we are just talking about EB's timeframe) were pre-eminent in their own region (greece) but they never managed to successfully expand beyond that, and frankly just weren't in the same league as the other two.