The Persians were sick and tired of the disruption caused by continuous fighting between the Greek city-states, with this spilling over into the Persian Empire, disrupting its peace and prosperity. They decided to bring these cities within the empire where they could be kept under control. Some of the Greek cities agreed to this, but the southern Greek cities opposed it and banded together to resist the takeover.
After the Persians failed, the Persians left them to go back to their usual destructive fighting each other.
Athens and its empire by Sparta and its allies, with financial support from Persia.
Persia.
the macedonians of course... No, not the Macedonians. Sparta had many cities aligned in a league to defeat Athens, and some had formerly been Athenian allies who turned their coats because Athens treated them too harshly. Also, Sparta later formed an alliance with an old enemy, Persia, which continued to meddle in Greek affairs after their defeat by Sparta and Athens many years earlier. Persia gave Sparta money for a fleet. nobody helped them Yes, somebody helped them. They could not have done it without help, especially from the Persians and the Syracusans. Read the history.
The Peloponnesian War was between Athens and Sparta. It was after the great Persian war, when Athens and Sparta worked together to defeat Persia. The Peloponnesian War was started because Sparta feared Athens may dominate them one day. There was a big battle between them, lasting for many years, but in the end, Sparta won.
Persia provided the funds for the Peloponnesian League to build and man a war fleet to match the hitherto superior fleet of Athens.
Athens and Sparta did not fight each other in isolation. They fought as allies and as adversaries in various conflicts over a couple of hundred years. So Athens did not defeat Sparta or Sparta defeat Athens. They were involved in wider conflicts in the battles.
they never joined forces
Pericles' decision to attack Sparta
There was no war between Persia and Sparta, and no specific battle between Sparta and Persia. Sparta was at times part of a Greek force fighting Persia, and at other times was allied to Persia. But there was no specific Sparta-Persia war or battle.
Persia.The Persian Empire.
After 27 years Athens, its fleet destroyed, was besieged and starved into surrender.
After 30 years they defeated a plague weakened Athens.