And yet, although this goddess enjoyed the same conditions as, for instance Jupiter Dolichenus whom the cohorts of Commagene introduced into Europe, it does not appear that she ever received the homage of many strangers; it does not appear, above all, that druidism ever assumed the shape of "mysteries of epona" into which Greeks and Romans would have asked to be initiated.
"The Oriental Religions in Roman Paganism"
Franz Cumont