At the head of this confederate council necessarily ranked Sparta, which was the master state of the Peloponnesus.

But in policy and debate, if not in arms, she appears always to have met with a powerful rival in Corinth, the diplomacy of whose wealthy and liberal commonwealth often counteracted the propositions of the Spartan delegates.

To this congress subsequently came the envoys of all the states that refused tribute and homage to the Persian king.
The institution of this Hellenic council, which was one cause of the salvation of Greece, is a proof of the political impotence of the old Amphictyonic league.

The Synedrion of Corinth (or rather of that Corinthian village that had grown up round the temple of Neptune, and is styled the ISTHMUS by the Greek writers) was the true historical Amphictyony of Hellas.
In the Isthmian congress the genius of Themistocles found an ampler sphere than it had hitherto done among the noisy cabals of Athens.

Of all the Greek delegates, that sagacious statesman was most successful in accomplishing the primary object of the confederacy, viz., in removing the jealousies and the dissensions that hitherto existed among the states which composed it.