Year 457 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Pulvillus and Augurinus or Cincinnatus and Vibulanus (or, less frequently, year 297 Ab urbe condita). The denomination 457 BC for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
Athenian forces block the routes back to the Peloponnese, so the Spartans decide to remain in Boeotia and await the Athenian attack. The Athenians and their allies, with 14,000 men under the command of Myronides, meet the Spartans at Battle of Tanagra. The Spartans win the battle, but they lose many men and so are unable to follow up on their victory.
The Athenians regroup after the battle and march into Boeotia. Led by Myronides, the Athenians defeat the Boeotians in the Battle of Oenophyta, and then destroy the walls of Tanagra and ravage Locris and Phocis.
Athens goes on to defeat Aegina later in the year, and to finish the construction of the Long Walls to the Athenian port of Piraeus (an action opposed by Sparta).
Boeotia, Phocis and Opuntian Locris become members of the Delian League. Athens now has enrolled in the Delian League all the Boeotian cities except Thebes. Aegina is forced to become a member of the League. It is assessed, with Thasos, for a yearly contribution to the League of 30 talents.