However , it maintained its political independence until the Roman conquest of Greece in 146 BC .
Sparta 's defeat by Thebes in the Battle of Leuctra in 371 BC ended Sparta 's prominent role in Greece .
Sparta maintained Sparta 's political independence until the Roman conquest Greece Greece in 146 BC .
Sparta 's defeat by Thebes in the Battle of Leuctra in 371 BC ended Sparta 's prominent role in Greece .