In this case Italian animism has held its own, not unsuccessfully, against imported polytheism. Our second instance, however, will show it less successful. When polytheism was spreading from Hellas over Italy, there would be no difficulty in adding the myths and cult of the Greek god Zeus bodily on to the worship of the Italian sky-spirit Jupiter. Nor would the process be much harder even when the Greek god and the Italian spirit were of totally different origin (as _e.g._ Hermes and Mercury, Kronos and Saturn), provided that some point of resemblance, in attribute or function, could be discovered between them. It was only one, and the least important of Hermes' functions, to protect traders, but it was quite enough to lead to the identification of the Greek god with the Italian spirit of gain (_Mercurius_, from _merces_). The case of Heracles, however, presented more difficulty; he was a hero, and the very conception of a hero was new to the Italians. Being new, it was, not unnaturally, misunderstood. The nearest parallel which Italian religion offered to a being who was in a way a man and yet was also a sort of god was the genius, who also was in a way the man himself, and yet was worshipped like a god. Heracles, therefore, was identified with the genius, his name was Latinised into the form _Hercules_ (cf. _Æsculapius_, from _Asclepios_), and the cults of the two were amalgamated. This amalgamation is the source and the explanation of some of Plutarch's _Roman Questions_. Plutarch was puzzled by the fact that on the one hand some elements in the cult of Hercules had counterparts in the worship of the Greek god, while on the other hand there were elements which received no explanation from a comparison of the cult of the Greek Heracles. Thus Plutarch is surprised to find an altar common to Hercules and to the Muses (_R. Q._ 59); but this is simply a loan from the ritual of the Greek Heracles, Musagêtês. On the other hand, as Plutarch informs us (_R. Q._ 60), there was an altar of Hercules from which women were excluded. This is a non-Greek element in the cult of Hercules, with which we may safely compare the fact, that whereas a man might swear "by his Hercules," a woman might not. Here the imported god has taken the place of the native genius both in the oath and at the altar; for the reason why the oath "me hercule" was restricted to men is that, until Hercules and the genius were identified, a man swore by his genius and a woman by her Juno. Again, in the time before Italy was invaded by the gods of Greece, in the time when temples were as yet unknown, the genius was worshipped and invoked, like other spirits, in the open air; and even after the Italians had learned from the Greeks that the gods were shaped in the likeness of men, and, like men, must have houses, an oath was felt to be more sacred and more binding if taken in the open air in the old fashion, than if sworn