An Athenian army, 15,000 strong, under the conduct of Myronides, entered Boeotia to protect its independence and delivered battle at Tanagra in 457 BC. The two armies met at Tanagra in a battle marked by bloody slaughter on both sides.
There was great slaughter on both sides; but the Thessalian horsemen deserted during the combat, and the Lacedaemonians gained victory.
The Spartan won the day but quickly withdrew fighting through the Megarid, their ability to capitalize in the victory an early sign of vulnerability to casualties because of the chronic lack of citizen manpower at Sparta.
The victory was not sufficiently decisive to enable the Lacedaemonians to invade Attica; but it served to secure them an unmolested retreat, after partially ravaging the Megarid through the passes of the Geraneia.
Battle of Tanagra (457 BC)