Persia had continually lost territory to the Greeks after the end of Xerxes I's invasion in 479 BC.
Athens also agreed not to interfere with Persia's possessions in Asia Minor, Cyprus, Libya or Egypt.
[2] Knowledge of the Peace of Callias comes from references by the 4th-century BC orators Isocrates and Demosthenes, as well as by the historian Diodorus.
[5] In any case, there seems to have been some agreement reached ending hostilities with Persia after 450/449, which allowed Athens to deal with the new threats from the other Greek city-states such as Corinth and Thebes, as well as Euboea, which rebelled from the Delian League shortly afterward.
Although Callias was also responsible for the Thirty Years' Peace with Sparta in 446 to 445 BC, the growing Athenian threat eventually led to the Peloponnesian War.