Athens and Sparta were once allies during the Persian Wars of 499 BC to 449 BC. The Persian Wars started when Cyrus the Great conquered Ionia in the 540s BC. Tyrants were appointed by the Persians to rule the cities in Ionia. The people were very unhappy with this and fought back in the Ionian Revolt. The Persian Empire tried to win control back and this started the war. Athens and Sparta fought as allies in this war in order to defeat the Persians. They were able to eventually defeat the Persians
After the Persian Empire was defeated, Athens and Sparta were the two superpowers in Greece. Athens eventually grew more powerful in a period called Pentecontaetia that starts at the end of the Persian War and lasts until the Peloponnesian War. After the Persians were defeated, Athens feared that they would try to retaliate. Because of that, Athens built Long Walls to protect themselves.
This created a lot of tension between Sparta and Athens. Sparta first realized that Athens was getting to powerful when Athens sent warriors to help Spartans with the Helots rebellion. Helots were the slave class in Spartan society. Sparta rejected the help from Athens while it accepted help from every other ally. This is because Sparta feared that the Athenian military would betray them and switch sides once inside the city. The rejected Athens then ended the alliance they shared with Sparta.
Athens and Sparta eventually went to war and fought for 27 years. This long war made Athens go bankrupt and lose morale. Sparta had the superior army over Athens but Athens had the better navy. Spartans attacked Athenians by land and the Athenian navy blocked food from reaching Sparta. According to the text, this left the two city states in a stalemate that slightly favored Athens. That was until one-third of the Athenian people were killed from a typhus plague.
Alcibiades fled the city state in the aftermath and joined Spartan forces. With his insider knowledge of the Athenian military, Alcibiades helped Sparta win the upper hand in the war. He was accused of having an affair with a Spartan leader's wife and now had to flee Sparta. He then got in with the Persians. He convinced the Persians to attack both city states instead of having just one enemy.
It was discovered that Alcibiades was using the Persians in order to get back with Athens' forces. This influenced Sparta and the Persians to establish a deal and worked together. The Persians were angered by Alcibiades and with this new deal with Sparta, they sent money, men, and combat equipment. This allowed Sparta to actively evade Athens and as a result the Athenians to surrender.
After the Peloponnesian War was over, Sparta put in an oligarchy form of government to govern Athens. This lasted for 8 months. During this time, Sparta told Athens to choose 30 men to govern the people of Athens. This group was called the Thirty Tyrants. The goal was to establish an interim government, eliminate enemies, and reform laws they disagreed with. This started a very violent portion of Greek history and Athens never returned to its pre-war glory again.