A common language led them to establish, by a mutual adoption of tutelary deities, a common religious ceremony, which remained in force after political considerations died away.

I take the Amphictyonic league to be one of the proofs of the affinity of language between the Pelasgi and Hellenes.

It was evidently made while the Pelasgi were yet powerful and unsubdued by Hellenic influences, and as evidently it could not have been made if the Pelasgi and Hellenes were not perfectly intelligible to each other.
Mr.Clinton (F.H., vol.i., 66), assigns a more recent date than has generally been received to the great Amphictyonic league, placing it between the sixtieth and the eightieth year from the fall of Troy.
His reason for not dating it before the former year is, that until then the Thessali (one of the twelve nations) did not occupy Thessaly.
But, it may be observed consistently with the reasonings of that great authority, first, that the Thessali are not included in the lists of the league given by Harpocratio and Libanius; and, secondly, that even granting that the great Amphictyonic assembly of twelve nations did not commence at an earlier period, yet that that more celebrated amphictyony might have been preceded by other and less effectual attempts at association, agreeably to the legends of the genealogy.
And this Mr.Clinton himself implies.
[80] Strabo, lib.

ix.
[81] Mueller's Dorians, vol.i.
[82] Probably chosen in rotation from the different cities.
[83] Even the bieromnemons (or deputies intrusted with religious cares) must have been as a class very inferior in ability to the pylagorae; for the first were chosen by lot, the last by careful selection.

And thus we learn, in effect, that while the hieromnemon had the higher grade of dignity, the pylagoras did the greater share of business.
[84] Milton, Hist.