History of the Peloponnesian War
Thucydides
Thucydides. History of the Peloponnesian War. Crawley, Richard, translator. London and Toronto: J. M. Dent and Sons Ltd.; New York: E. P. Dutton and Co., 1914.
Some cavalry also joined the Athenians from their Thessalian allies; but these went over to the Lacedaemonians during the battle.
The battle was fought at Tanagra in Boeotia. After heavy loss on both sides victory declared for the Lacedaemonians and their allies.