I know the East is tempting, I'm in a more or less similiar position as Makedonia in my current campaign. Wiht the onky difference that I can defeat the Seleukidai, of course, but that doesn't mean I have always been able to do so. You see, I used to be afraid of the Grey Death with their Argyraspides and Hetairoi, so I exploited AI weakness by raiding and pillaging he southern Anatolian coast as well as the Levant through amphibious assaults. If you do that and destroy their barrackses and generally any building that is destructible, soon the quality of their armies will drop drastically. Then, you can consider launching an offensive

Maion