The ones that have attained a measure of political power have always had a major impact...and always for the negative but you did not specify a "positive" impact. The obvious culprits are xtianity and islam but the ritual sacrifices of the South American cultures...even allowing for Spanish exaggeration can hardly be claimed a positive impact either. To quote Gibbon:
Quote:The various modes of worship which prevailed in the Roman world were all considered by the people as equally true; by the philosopher as equally false; and by the magistrate as equally useful.
