If this be so, we are carried back by this sacrifice to the very beginnings of Rome, and get a useful clue to the nature of the god Janus. The Rex sacrorum was the special representative in later times of the king; the king, living in the Regia, was the equivalent in the State of the head of the household. The two most important and sacred parts of the house are the door (ianua, ianus), and the hearth (vesta)[1253], and the numina inhabiting and guarding these are Janus and Vesta, who, as is well known, were respectively the first and the last deities to be invoked at all times in Roman religious custom. The whole house certainly had a religious importance, like everything else in intimate relation to man; and Macrobius is not romancing when he says (quoting _mythici_) ‘Regnante Iano omnium domos religione et sanctitate fuisse munitas[1254].’ But the door and the hearth were of special importance, as the folk-lore of every people fully attests; and it is hardly possible to avoid the conclusion that we must look for the origin of Janus in the ideas connected with the house-door, just as we have always found Vesta in the fire on the hearth. Whatever be the true etymology of Janus, and however wild the interpretations of his nature and cult both in ancient and modern times, we shall always have firm ground to stand on if we view him in relation to the primitive worship of the house[1255]. There is hardly an attribute or a cult-title of Janus that cannot be deduced with reason from this root-idea. The old Roman scholars, who knew as little about Janus as we do, started several explanations of a cosmical kind, which must have been quite strange to the average Roman worshipper. He was a sun-god[1256], and his name is the masculine form of Diana (= moon); he was the _mundus_, i. e. the heaven, or the atmosphere[1257]. These were, of course, mere guesses characteristic of a pedantic age which knew nothing of the old Roman religious mind. If Janus ever had been a nature-deity, his attributes as such were completely worn away in historical times, or had lost their essential character in the process of constant application to practical matters by a prosaic people. How far the Roman of the Augustan age understood his great _deorum deus_ may be gathered from Ovid’s treatment of the subject, itself no doubt a poetical version of the learned speculation of Varro and others. The poet ‘interviews’ the deity with the object of finding out the lost and hidden meaning of his most obvious peculiarities, and the old god condescends to answer with a promptness and good temper that would do credit to the victims of the modern journalist. The curious thing is that the real origin, humble, simple, and truly Latin, escaped the observation both of the interviewer and the deity. Before I state more definitely the grounds on which this simple explanation of Janus is based, it will be as well to deal shortly with the more ambitious ones.