Answer:
It was an ancient Greek War fought by the Delian League (led by the Athens) against the Peloponnesian league (led by Sparta). the major cause of it was the Battle of Sybota. this war marked the end of the Golden Age of Greece and the fall of Athens which was once the strongest city-state in Greece. Athens was then absorbed into the Spartan Empire causing the power in Greece to shift dramatically. hope this helped!