Callias (kăl´ēəs), fl. 449 BC, Athenian statesman; he was related to Cimon and also to Aristides. He distinguished himself at the battle of Marathon (490 BC) and was a three-time winner of the Olympic chariot races. Callias was sent to Susa to negotiate for peace c.449 BC The result of his work was an agreement usually called the Peace of Callias (or Treaty of Callias); by it Artaxerxes I agreed to respect the independence of the Delian League and its members and to send no warships into Greek waters; in return Athens agreed not to interfere with Persian "influence" in Asia Minor, Cyprus, and Egypt. There is doubt that such a treaty was actually ever drawn up; however, peace did exist between Persia and the cities of Greece until the end of the century. According to ancient historians, when Callias returned to Athens he was fined 50 talents for betraying the city. Callias was also supposed to have been one of the negotiators of a treaty between Athens and Sparta (446–445 BC) that resulted in 30 years of peace.

Callias, d. c.370 BC, Athenian leader, one of the generals of the Peloponnesian War. In his old age Callias was one of the ambassadors sent to Sparta with Callistratus to negotiate a peace treaty in 371 BC The treaty was ineffective, and friction between Epaminondas of Thebes and Agesilaus II of Sparta became acute. Callias was a rich man and his wealth was ridiculed by his contemporaries, including Aristophanes. His house is the scene of Xenophon's Symposium and Plato's Protagoras.