Sparta wins the war
September 2016 - After they defeated the Sicilian Expedition in 415 BC, and with the help of the Athenian general Alcibiades, who had gone over to the Spartan side, the Spartans began to win more battles against Athens. Alcibiades taught the Spartans how to fight naval battles. But by 412 BC Alcibiades had gotten very unpopular in Sparta as well as Athens. Plutarch says Alcibiades was suspected of sleeping with the Spartan queen, but we don't know whether that is true.
In any case, Alcibiades left the Spartans and fled to the protection of a Persian satrap, Tissaphernes, in the old kingdom of Lydia. Alcibiades convinced Tissaphernes (tiss-ah-FUR-nees) to give money to the Athenians, if the Athenians would let Alcibiades be a general again and end the democracy, putting in an oligarchy instead run by the generals. The Athenians agreed to do this, if it would help them win the war against Sparta. The generals did take power, but in the end Tissaphernes didn't give the money he had promised, so Alcibiades didn't get to be a general. Some of the Athenian allies went over to the other side, and the Athenian oligarchy began negotiating with the Spartans for a surrender.
But just at this point, the Athenian navy, which was anchored off the island of Samos, heard about the oligarchs getting power in Athens, and wanting to surrender to Sparta. The soldiers were very angry about losing their democracy, and about surrendering, and they elected Alcibiades their general. They demanded that the Athenians put the democracy back in power immediately.
The Athenians were going to say no, but just at this point the negotiations to surrender to Sparta failed, and the Spartans attacked and the Athenian fleet in Athens was destroyed. So the Athenians agreed to do what the fleet at Samos wanted: they restored the democracy, let Alcibiades be their general, and stopped trying to surrender to Sparta. The Persians began to give money to Sparta instead of Athens.
Now the Spartans had a smart idea: they used their navy to block the Hellespont, where ships came through bringing food to Athens. Alcibiades tried to break the Spartan blockade, and he did win some victories, but in the end, thanks to Persian money, the Spartans got control. The Athenians started to fight among themselves, and by 407 BC they had fired Alcibiades again. He was angry, washed his hands of the whole war, and retired.
Slowly the Athenians began to starve, as the Spartans stopped their food ships from getting through. By 404 BC, with many Athenians already dead of starvation, the Athenians surrendered unconditionally, and the Spartans made them pull down their city walls.
Learn by doing: hold a debate between Spartans and Athenians about terms of surrender
More about the Hellenistic period
The Last of the Wine, by Mary Renault (a fictionalized account)
Oxford First Ancient History, by Roy Burrell and Peter Connolly (1997). Lively interviews and pictures make the ancient Mediterranean come to life. For teens.
A Brief History of Ancient Greece: Politics, Society, and Culture, by Sarah Pomeroy and others (2004). For college students.
The Peloponnesian War, by Donald Kagan (reprinted 2003). Kagan is basically a military historian, and a conservative. This is a shortened version of his four-volume book about the same war, for the popular reader.
The Peloponnesian War 421-404 BC, by Philip De Souza (2002). A more liberal view, with emphasis on the role played by the Persians, and less on the strategies of individual battles.
Landmark Thucydides: A Comprehensive Guide to the Peloponnesian War,
by Thucydides, with commentary by Robert B. Strassler (1998). The original account of the war by an Athenian general turned historian.