DĪVĪNĀTĬO (μαντική), a power in man which foresees future things by means of those signs which the gods throw in his way. Among the Greeks the _manteis_ (μάντεις), or seers, who announced the future, were supposed to be under the direct influence of the gods, chiefly that of Apollo. In many families of seers the inspired knowledge of the future was considered to be hereditary, and to be transmitted from father to son. To these families belonged the Iamids, who from Olympia spread over a considerable part of Greece; the Branchidae, near Miletus; the Eumolpids, at Athens and Eleusis; the Telliads, the Acarnanian seers, and others. Along with the seers we may also mention the Bacides and the Sibyllae. Both existed from a very remote time, and were distinct from the manteis so far as they pretended to derive their knowledge of the future from sacred books (χρησμοί) which they consulted, and which were in some places, as at Athens and Rome, kept by the government or some especial officers, in the acropolis and in the most revered sanctuary. The Bacides are said to have been descended from one or more prophetic nymphs of the name of Bacis. The Sibyllae were prophetic women, probably of Asiatic origin, whose peculiar custom seems to have been to wander with their sacred books from place to place. The Sibylla, whose books gained so great an importance at Rome, is reported to have been the Erythraean: the books which she was said to have sold to one of the Tarquins were carefully concealed from the public, and only accessible to the duumvirs. Besides these more respectable prophets and prophetesses, there were numbers of diviners of an inferior order (χρησμολόγοι), who made it their business to explain all sorts of signs, and to tell fortunes. They were, however, more particularly popular with the lower orders, who are everywhere most ready to believe what is most marvellous and least entitled to credit. No public undertaking of any consequence was ever entered upon by the Greeks and Romans without consulting the will of the gods, by observing the signs which they sent, especially those in the sacrifices offered for the purpose, and by which they were thought to indicate the success or the failure of the undertaking. For this kind of divination no divine inspiration was thought necessary, but merely experience and a certain knowledge acquired by routine; and although in some cases priests were appointed for the purpose of observing and explaining signs [AUGUR; HARUSPEX], yet on any sudden emergency, especially in private affairs, any one who met with something extraordinary, might act as his own interpreter. The principal signs by which the gods were thought to declare their will, were things connected with the offering of sacrifices, the flight and voice of birds, all kinds of natural phenomena, ordinary as well as extraordinary, and dreams.--The interpretation of signs of the first class (ἱερομαντεία