The Thessalians invaded Boeotia as far as Thespiae, more than 200 years before Leuctra (according to Plutarch), , which might have given Thespiae the impetus to join the Boeotian League. But elsewhere Plutarch gives a date for the Thessalian invasion as shortly preceding the Second Persian War. Herodotus suggests that Thespiae had been a member of the league as long as Thebes had been. Following the Persian Wars, Thespiae provided two Boeotarchs to the league, rather than one; perhaps one for the city and one for the districts under its control.