The Phyle Campaign was the civil war that resulted from the Spartan

History of Sparta

The History of Sparta describes the destiny of the ancient Dorian Greek state known as Sparta from its beginning in the legendary period to its forced incorporation into the Achaean League under the late Roman Republic, its conquerors, in 146 BCE, a period of roughly 1000 years...

 imposition of a narrow oligarchy on Athens

Classical Athens

The city of Athens during the classical period of Ancient Greece was a notable polis of Attica, Greece, leading the Delian League in the Peloponnesian War against Sparta and the Peloponnesian League. Athenian democracy was established in 508 BC under Cleisthenes following the tyranny of Hippias...

 (see Thirty Tyrants

Thirty Tyrants

The Thirty Tyrants were a pro-Spartan oligarchy installed in Athens after its defeat in the Peloponnesian War in 404 BC. Contemporary Athenians referred to them simply as "the oligarchy" or "the Thirty" ; the expression "Thirty Tyrants" is due to later historians...

) and resulted in the restoration of Athenian democracy.

Prelude

The Thirty were short of funds and this led them to persecute wealthy Athenians of whatever political views.
Many fled to Boeotia and Corinth

Ancient Corinth

Corinth, or Korinth was a city-state on the Isthmus of Corinth, the narrow stretch of land that joins the Peloponnesus to the mainland of Greece, roughly halfway between Athens and Sparta. The modern town of Corinth is located approximately northeast of the ancient ruins...

 who offered asylum in defiance of Sparta.

The campaign

Due to both deference to Sparta and to their cash shortage the Thirty had left Athens' border forts ungarrisoned which allowed a group of Athenian exiles to seize the fort of Phyle in 404/403 BCE. The leader of the exiles, initially only some 70 strong, was Thrasybulus

Thrasybulus

Thrasybulus was an Athenian general and democratic leader. In 411 BC, in the wake of an oligarchic coup at Athens, the pro-democracy sailors at Samos elected him as a general, making him a primary leader of the successful democratic resistance to that coup...

 who had a reputation as a moderate democrat and so ideal to unite all democratic opponents of the thirty.. A force of Athenian cavalry and Spartans was sent against Phyle, but was defeated in two surprise attacks by Thrasybulus. Thrasybulus then marched on Piraeus and defeated the force the thirty sent against him at the Battle of Munychia

Battle of Munychia

The Battle of Munichia was fought between Athenians exiled by the oligarchic government of the Thirty Tyrants and the forces of that government, supported by a Spartan garrison...

.

Sparta first responded by sending Lysander with a force of mercenaries who clearly intended simply to place the thirty back in power. Very quickly, however, Sparta sent King Pausanias

Pausanias of Sparta

Pausanias King of Sparta from 409 BC. He was in frequent conflict with the Ephors. Aristotle said that he tried to overthrow them. Army leader Lysander sent a letter to him, requesting help against Thebes, but it was intercepted...

 with a levy of the Peloponesian League. Pausanias defeated the democrats in the Battle of Piraeus However he opened negotiations and accepted the restoration of democracy but insisted on the separation Eleusis as a safe haven for the oligarchs.

Aftermath

Lysander's faction at Sparta was furious and along with King Agis brought Pausanias to trial to the end of 403 BCE. The exact charge is uncertain but the essence was presumably that he had been soft on Athens. Fifteen of the Gerousia

Gerousia

The Gerousia was the Spartan senate . It was made up of 60 year old Spartan males. It was created by the Spartan lawgiver Lycurgus in the seventh century BC, in his Great Rhetra...

, including Agis, voted guilty and 14 against but all 5 Ephors

Ephor

An ephor was the leader of ancient Sparta and shared power with the Spartan king...

voted non guilty so he was acquitted.