[Sidenote: Rationalistic theory of the duties of the Vestals rejected.] It has, indeed, been held that the Vestals were of old the king’s daughters, who were kept at home and forbidden to marry for no other reason than that they might devote themselves to the domestic duties of drawing water, mopping the house, tending the fire, and baking cakes.[654] But this rationalistic theory could hardly explain the superstitious horror which the infidelity of a Vestal always excited in the Roman mind. Customs which begin in reason seldom end in superstition. It is likely, therefore, that the rule of chastity imposed on the Vestals was based from the first on a superstition rather than on a mere consideration of practical convenience. The belief that the Vestals were the spouses of the fire-god would explain the rule.[655] We have seen that the practice of marrying women to gods has been by no means uncommon. If the spirit of the water has his human wife, why not the spirit of the fire? Indeed, primitive man has a special reason for thinking that the fire-god should always be married. What that reason is, I will now try to explain. [Sidenote: The Vestal fire of later times was a continuation of the fire on the king’s hearth.] But first it is necessary to apprehend clearly that the Vestal fire of republican and imperial Rome was strictly the successor or continuation of the fire which in the regal period had burned on the king’s hearth. That it was so appears plainly from the stories of the birth of Romulus and Servius Tullius, which shew that Vesta was believed to be worshipped at the royal fireside by maidens who were either the king’s daughters or his slaves. This conclusion is amply confirmed by a study of the temple of Vesta and the adjoining edifices in the Roman Forum. For the so-called temple of the goddess never was, strictly speaking, a temple at all. This fact we have on the authority of Varro himself, the greatest of Roman antiquaries.[656] The little round building in which the sacred fire always burned was merely a copy of the round hut in which the king, like his [Sidenote: The round temple of Vesta a copy of the ancient Italian hut.] subjects, had dwelt in days of old. Tradition preserved a memory of the time when its walls were made of wattled osiers and the roof was of thatch;[657] indeed, with that peculiar clinging to the forms of the past which is characteristic of royalty and religion, the inmost shrine continued down even to late times to be fashioned of the same simple materials.[658] The hut of Romulus, or what passed for it, constructed of wood, reeds, and straw, was always preserved and carefully repaired in the original style. It stood on the side of the Palatine hill facing the Circus Maximus.[659] A similar hut, roofed with thatch, was in like manner maintained on the Capitoline hill, and traditionally associated with Romulus.[660] The so-called temple of Vesta in historical times stood not on any of the