Pausanias was a Spartan general of the 5th century B.C.. He was the nephew of Leonidas I and served as regent after his uncle's death, as Leonidas' son, Pleistarchus, was still under-age. He was responsible for the Greek victory over Mardonius and the Persians at the Battle of Plataea in 479 B.C., and was the leader of the Hellenic League created to resist Persian aggression during the Greco-Persian Wars.
After the Greek victories at Plataea and the Battle of Mycale, the Spartans lost interest in liberating the Greek cities of Asia Minor. However, when it became clear that Athens would dominate the Hellenic League in Sparta's absence, Sparta sent Pausanias back to command the League's military.
In 478 B.C. Pausanias, the Spartan regent, was suspected of conspiring with the Persians and was recalled to Sparta, however he was acquitted and then left Sparta of his own accord, taking a trireme from the town of Hermione. After capturing Byzantium Pausanias released some of the prisoners of war who were friends and relations of the king of Persia, he made out that the prisoners had escaped. He sent a letter to the King, Xerxes (son of Darius), saying that he wished to do him favours and that he wished to marry the King’s daughter and help to bring Sparta and Greece under Persian control. After receiving a letter back from Xerxes in which he agreed to his plans, Pausanias started to dress and act in a Persian way. Many Spartan allies joined the Athenian side because of Pausanias’ arrogance and high-handedness. The Spartans recalled him once again, and Pausanias returned because he didn’t wish to be suspected of Persian sympathies, on his arrival in Sparta the ephors had him imprisoned but he was later released. Nobody had enough evidence to convict a member of the royal family; even though some Helots gave evidence that he had offered certain Helots their freedom if they joined him in revolt. One of the messengers that Xerxes and Pausanias had been using to communicate opened the letter and provided almost all the evidence that the Spartan ephors needed. Later they eavesdropped on Pausanias to ensure that the evidence was accurate, having decided that it was they planned to arrest Pausanias in the street but he was tipped off and escaped by running to the temple of the Goddess of the Brazen House. The ephors walled up the doors, put sentries outside and proceeded to starve him out. When Pausanias was on the brink of death they carried him out and, as soon as he was brought outside, he died. After burying him nearby, the god at Delphi, Apollo, told the Spartans to move Pausanias’ tomb to the place where he died. (Thucydides 1.128-136) Kimon and the Athenians then became the leaders of the Hellenic League, which gave them the clout necessary to create the Delian League.