Sparta led a coalition of Peloponnesian city-states which we today call the Peloponnesian League. It was already in existence before the Persian Wars - comprising the Dorian city-states of southern Greece.
The Persian Empire and an alliance of Greek city-states led first by Sparta and then Athens.
It led the anti-Persian alliance of Greek city-states.
On one side, Athens. On the other, Sparta.
The Persian Empire .
Yes.
Segeral city states formed an alliance after the Persian wars to make it possible to combat the Persians.
The Persian king, and first Sparta then Athens on the Greek side.
The Persian Wars
Afterwards, Athens converted the alliance it had led in the latter stages into an empire of its own, and used and misused those resources, leading to the peloponnesian War against the alliance led by Sparta, which devastated the Greek world.
The one of 480-479 BCE.
Its Leonidas, king of Sparta during the Persian wars.
Self defence.