This development of modern superstition supplies a clue for tracing the evolution of ancient Greek religion, which has hitherto been missed by those who have dealt with the subject[709]. They have generally compared with the modern Greek superstition similar beliefs and customs prevalent throughout the Balkans and even beyond them, and have thence inferred that the practice of sacrificing to the _genii_ of sites selected for building was of Slavonic importation. The wide distribution of the superstition in the Balkans, especially among the Slavonic peoples, is a fact; but the inference goes too far. To Slavonic influence I impute the recrudescence of the superstition in its most barbarous form, involving human sacrifice, during the Middle Ages. Ancient history, even ancient mythology, contains no story so suggestive of barbarity as one brief statement made by Suidas: ‘At St Mamas there was a large bridge consisting of twelve arches (for there was much water coming down), and there a brazen dragon was set up, because it was thought that a dragon inhabited the place; and there many maidens were sacrificed[710].’ The date of the events to which the passage refers cannot be ascertained; but I certainly suspect it to be subsequent to the Slavonic invasion of Greece. Yet even so the Slavs did not initiate a new custom but merely stimulated the native belief that _genii_ required sacrifice in compensation for the building of any edifice on their domains. This belief dated from the Homeric age--nay, was already old when the Achaeans built their great wall with lofty towers, a bulwark for them and their ships against the men of Ilium.