Rome II: Wrath of Sparta.
As the Spartans, my goal is to subdue the growing Athenian Empire and keep them in check, whilst also building a subtle Greek hegemony for the benefit and glory of Sparta. (I'm on my mobile right now, so forgive me for the lack of names) My Spartan King started things off by gathering all available troops and moving north towards Argos. My general near the Boeotian and Thessalian Leagues stations himself in the Spartan village to guard the famous Hot Gates and to provide allied support against any Athenians. Before the ending of the first month (turn), I make trade with anyone and everyone (minus Argos), as well as offering non-aggression pacts for money. It bodes well, as I get almost 7000 immediately and a fairly secure surrounding border.
In the next month, my King heads north just shy of a full army and lays siege on Argos. However, my goal is to not conquer, but instead build a subtle empire. Before I attack the city, I offer Argos peace, trade, and an opportunity for them to be my client state. They ecstatically say yes and agree to my terms, and a battle is prevented while levied troops are gained. My King continues to move north.
A few months later, and after acquiring a general from the Olympic Games, I convince my northern neighbor, Eris, to join my Spartan confederation, allowing me to control their only army stack of 17 units. I rename the army, Sons of Eris, and offer Argos a similar deal. They accept and I gain control of another army and my first navy. The new army gets mixed in with the Sons of Eris, the Argos general goes to Sparta for politics, and the new Argos fleet of mine guards the seas.
Fast forward through a few battles and more similar diplomacy, and my King is now across the Aegean Sea with a few supporting generals, poised to strike into the Persian Empire, who has suspiciously laid low in recent months. The Thessalian League assimilated into the Spartan confederation, Epirus and Makedon are my client states along with a few other Greek City States, and Athens has recently accepted peace, but with no non-aggression. The Boeotian League had gotten greedy in the past years and laid siege to Athens. I, along with my fellow Korinthians were able to foil the siege on Athens and drive back the Boeotians home, where I demanded peace and payment as I said siege on their capital. The Boeotian League now pays me tributaries while the rest of my "free" Greeks join my King to lay waste and conquer the Persian world.
tl;dr - a whole lot of threaten sieges and war in order to build a host of client states and Spartan confederations. Athens backs down while the Persians prepare to kiss the ground.