Dating back to 449 BC, Sparta and Athens have always had an alliance, but as time passed this balance slowly began to crumble, with one feeling threatened by the 'other. Before any signs of instability, the Spartans and Athenians enjoyed a bonded partnership. After their domination of the Persian War, both states slowly became aware of each other's growing power. Time passed and the Spartans began to become aware of other states, feeling suspicious and paranoid of them (Fox, 170). Neither state was particularly responsible for the strain on their peace treaty, nor for the war, which occurred as both states grew. Eventually, the two states had clashed enough and declared war. Although the Spartans gave the Athenians a chance to back down and temporarily stall the war, the two states would never be equal, their allies resented each other far too much. The growing thirst for power was bound to take over sooner or later. Finally, after 7 years of worrying tensions, Sparta could wait no longer and declared war on Athens (Fox, 167). Although the Athenians and Spartans lived together peacefully for so long, they existed in a fragile balance that would eventually lead to war. Although the Spartans and Athenians fought for almost 20 years, there was a time when they lived in harmony. Nearly 15 years before the Troubles, the Athenians and Spartans fought together in the Persian War. During the war against the Persians, the Spartans prospered in their fight against the Persians, but as time passed, the Persians began to become stronger. After losing their fighting streak, the Athenians came to help the Spartans and end Persian rule once and for all (The Delian League, 1). After defeating the Persians in 449 BC, the... middle of paper ...... each other until they were no more. From the Persian War to the Peloponnesian War, both states have changed over the years. Starting with their greatest alliance but first moment of subtle rivalry, the Persian War. Even though they were indiscriminately competing against each other, they could not have dominated without each other. Then there were the two blows to the peace treaty. The first blow was Athenian assistance in the battle between Corinth and Corycra. The second move was the idea of ​​burning down the city of Corinth. Although these were remarkable errors, the Athenians saw nothing wrong with them. Finally, there was war. In 431 BC the Peloponnesian War broke out between the two allies, after all they had endured their alliance was over. War was inevitable, even though they had lived in peace for so long, one or the other was destined to break out..