The Boeotian or Theban War broke out in 378 BCE as the result of a revolt in Thebes against Sparta. The war would last six years.

Outbreak of the War

In 378 BCE a revolt in Thebes led to the assassination of the ruling 3 man junta and the expulsion of the Spartan garrison. An expedition against Thebes was mounted led by Kleombrotus achieved little but left a garrison in Thespiae

Thespiae

Thespiae was an ancient Greek city in Boeotia. It stood on level ground commanded by the low range of hills which runs eastward from the foot of Mount Helicon to Thebes, near modern Thespies.-History:...

 under Sphodrias. That winter Sphodrias attempted a raid on Pireus which ended in fiasco. Sphodrias had not acted under orders and was brought to trial. However, he was acquitted which led Athens to declare for Thebes

The War

Two expeditions against Thebes were led by King Agesilaus achieved little. Mark Munn argues that it is likely that the Dema wall was built at this time to defend Attica. An expedition in 376 BCE led by King Keombrotus was blocked at the passes of Kithairon

Kithairon

Kithairon is a mountain range about 10 mi long, in central Greece, standing between Boeotia in the north and Attica in the south. It is mainly composed of limestone and rises to 4,623 ft...

. Sparta then sent a fleet in and attempt to blockade Athens. The result was the defeat of the Spartan fleet at the Battle of Naxos

Battle of Naxos

At the Battle of Naxos the new Athenian fleet of Chabrias decisively defeated the Spartans. This was the beginning of Athens's recovery of its Aegean hegemony following its loss in the Peloponnesian War. The victory was decided by Phocion's courageous and skillful action on the left wing...

 at the hands of a predominately Athenian fleet commanded by Chabrias

Chabrias

Chabrias was a celebrated Athenian general of the 4th century BC. In 388 BC he defeated the Spartans and Aeginetans under Gorgopas at Aegina and commanded the fleet sent to assist Evagoras, king of Cyprus, against the Persians. In 378, when Athens entered into an alliance with Thebes against...

 in 376 BCE. In 375 BCE Athens mounted 2 successful expeditions - one to the north Aegean under Chabrias and a second round the Peloponnese to North West Greece under Timotheos son of Konon who won the battle of Alyzeia

Alyzeia

Alyzeia was an ancient Greek city in Acarnania. In 375 BCE Timotheos son of Konon won a battle near Alyzeia during the Boeotian War....

 in Akania

Akania

Akania is a village in Chandpur District in the Chittagong Division of eastern Bangladesh....

.
In 375 BCE there was a renewal of the Kings peace

Peace of Antalcidas

The Peace of Antalcidas , also known as the King's Peace, was a peace treaty guaranteed by the Persian King Artaxerxes II that ended the Corinthian War in ancient Greece. The treaty's alternate name comes from Antalcidas, the Spartan diplomat who traveled to Susa to negotiate the terms of the...

 but this lasted no longer than a few months. The capture of Platea put the Theban-Athenian under strain. The Plateans were expelled by the Thebans and found asylum in Athens where they were a strong voice against Thebes. Though the alliance held, Athens insisted on negotiations with Sparta. A peace treaty was agreed but things went seriously awry at the signing - Epaminondas insisted that he should sign for the Boeotians as a whole rather than just Thebes, at which the Spartan king Agesilaus struck the name of Thebes off the list of signatories.

After the Peace

Most of Greece implemented the treaty which meant that Thebes faced the Spartan expedition against her alone. However the resulting battle at Leuktra

Battle of Leuctra

The Battle of Leuctra was a battle fought on July 6, 371 BC, between the Boeotians led by Thebans and the Spartans along with their allies amidst the post-Corinthian War conflict. The battle took place in the neighbourhood of Leuctra, a village in Boeotia in the territory of Thespiae...

would be a decisive Spartan defeat.