From these, however, a second duad proceeds, Ocean and Tethys, this generation not being effected by copulation, nor by any conjunction of things separated, nor by division, nor according to a certain abscission, for all these are foreign from the Gods; but they are accomplished according to one union and indivisible conjunction of powers. And this union theologists are accustomed to call marriage. For marriage, as the theologist Orpheus says, is appropriate to this order. For he calls Earth the first Nymph, and the union of her with Heaven the first marriage; since there is no marriage in the divinities that are in the most eminent degree united. Hence there is no marriage between Phanes and Night, who are intelligibly united to each other. And marriage appears on this account to be adapted to the Heaven and Earth which we are at present considering, so far as they adumbrate the intellectual Heaven and Earth; which the sacred laws of the Athenians likewise knowing, ordered that the marriages of Heaven and Earth should be celebrated, as preparatory to initiation into the mysteries. Directing their attention to these also, in the Eleusinian mysteries looking upward to the heavens, they exclaimed, O son! but looking downward to the earth, O parent! According to this union, therefore, in conjunction with separation, Heaven and Earth produce through their goodness Ocean and Tethys. Or rather, they do not immediately produce these, but prior to these two monads, two triads, and duple hebdomads, among which are Ocean and Tethys. And the monads indeed, together with the triads, remain with the father. But of the hebdomads, Ocean, together with Tethys, abide, and at the same time proceed. All the rest, however, proceed into another order of Gods. And this indeed is the mode of their subsistence in the intellectual order. But here, Plato entirely omits the causes that abide in the father, but delivers to us those that proceed and at the same time abide, because his intention is to speak of the Gods that are the fabricators of generation. To these, however, progression, motion, and difference, are adapted, and a co-arrangement of the male with the female; in order that there may be generation, that matter may be adorned with forms, and that difference may be combined with sameness. Hence Plato commences from the duad, proceeds through it, and again returns to it. For the duad is adapted to material natures, as well as difference, on account of the division of forms about matter. Having mentioned a duad, likewise, he begins from Earth; for this is more adapted to things pertaining to generation.