Finally the war broke out. Little city of the Plataeo wich belonged to the Beotean Legue decided to become independent. City of Thebes wanted to choke the revolt but were forced back. Plataeoans seeked the support of the Athenean Empire while Thebeans turned to Athens long enemy-Sparta.

First half of the war didn't have any outcome favorable to each side.

As Pericles persuaded Athenian to relay on the sea people living in the country side moved to the city and left their belongings and land to devastation by Spartans.

First Athens wasn't doing that bad. Their solders raided the coast of Peloponnesus, devastated territory of Megara and expelled people of the island of Aegina, living Athenians from the crowded city. Then Pericles secured his friendship with king of Macedonia and Thrace on the North.

On the winter of the first year of the war, a public funeral was held for solders who had died.

During summer time Spartans invaded Attica keeping everybody inside the walls. Then Athens fell victim to its surcumstances. Plague struck overcrowded Athens taking lives of quarter or may even one third of its population. Plague returned two more times-(429B.C. and 427/6 B.C.) killing Pericles and his two sons. Nobody knows still what kind of decease did all this killing.

The affects were horrible. Athens was able to fill the military rolls again in 415, but the older generation that usually filled the offices and provided leadership was not replaced with ease.

There was no more leaders after the death of Pericles to continue the war effective. New category of leaders had developed. They did not lead the people but instead were led by demos-so they were called Demagogues.

In 430 B.C. Platidea surrendered And in 428 B.C. one of the most important allies of Athens-Lesbos decided to revolt against the empire. Lesbos was one of the three allies that maintained a fleet.. Because Sparta didn't take adequate action Athens recovered Les bos after long siege.

In 425 B.C. Athens obtained a fort in Messenia called Pylos.Spartans answered with force of hoplites to fight the Athenians but the mission failed as Spartans lost control of the island of Sphakteria and to save its solders Sparta asked for a piece. Athenian assembly rejected piece offer influenced by Kleon.

In 424 B.C. Athenians decided to invade Beotia but weren't successful. In mean time Spartan General Braisidas marched north to court Athenian subjects. As a result Amphilopolis was lost to Spartans. That city was very important because it controlled the crossing of Strymon river-main route in that area. Athens lost good resources of timber and silver.

In 423 Athens and Sparta concluded a one year truce. But it was short lived since the city of Scione revolted against Athens. A fleet was sent out and in 421 B.C. city fell to the Athens. All the man in the polis were killed and woman were enslaved.

In 422 B.C. Kleon took athenian army to reclaim Amphilopolis. In the ensuing battle both Kleon and Spartans Brasidas fell with victory on the Spartas side.

Both sides needed piece. Sparta wanted its hostages from Pylos and Athens suffered great losses in man power. Sparta and Athens signed a treaty called Piece of Nicias.