Athensball was the one to win the war against the huge Persiaball. At that time it had become the de-facto leader of the Greek states. He led the other greek cityballs to victory against Persiaball, although some of the other cities didn't like its leading (like Spartaball).
After it won the Greco-Persian War, it continued acting like the "Leader of Ancient Greeceball" which made him disliked by many. After a big conflict with Ancient Corinthball and Spartaball (and as we all know, having war with Spartaball isn't the best thing that could happen to you),Thebesball and Macedonball joined. Athensball ultimately lost and it became a client state to Spartaball and to Macedonball later.