If you’ve ever watched a video on ancient Greek history, you’ll know that the Greeks were constantly at each other’s throats. Fragile coalitions were made, just to be broken when the other side proved to be stronger or promised a better share of the loot.
Perhaps the key question is, how to keep the third parties out of your way and yet use them to reach your goals?
In Imperiums: Greek Wars the Greek world is tightly knit, often a war between two states can start a chain reaction. Do you have a strategic ally who you need in a war against a common enemy? Only to find them too stretched to assist because they have a second front with a petty city-state on another border?
Use your position to send a kind request to the leaders of the city-state warmongers, asking them to sign a peace treaty with your strategic ally. If they consent, you untie the hands of your coalition partner and earn their gratitude, this also counts! If they refuse, turn the tide against them by sending envoys to their neighbouring states asking them to declare war on the city-state. That will teach them not to play tough with you.
Using these third party requests you can play one opponent off against another and with a bit of foresight you can sail through the intrigues and shaky political deals with a following wind.
Perhaps a little warning here though, the AI is very competent and can use the same techniques against you. You simply need to be smarter than it :)