Plutarch, De Iside et Osiride
Frank Cole Babbitt, Ed.

They think that the risings of the Nile have some relation to the illuminations of the moon ; for [p. 105] the greatest rising,¹ in the neighbourhood of Elephantinê, is twenty-eight cubits, which is the number of its illuminations that form the measure of each of its monthly cycles ; the rising in the neighbourhood of Mendes and Xoïs, which is the least, is six cubits, corresponding to the first quarter. The mean rising, in the neighbourhood of Memphis, when it is normal, is fourteen cubits, corresponding to the full moon.

The Apis, they say, is the animate image of Osiris,² and he comes into being when a fructifying light thrusts forth from the moon and falls upon a cow in her breeding-season.³ Wherefore there are many things in the Apis that resemble features of the moon, his bright parts being darkened by the shadowy. Moreover, at the time of the new moon in the month of Pharnenoth they celebrate a festival to which they give the name of ‘Osiris's coming to the Moon,’ and this marks the beginning of the spring. Thus they make the power of Osiris to be fixed in the Moon, and say that Isis, since she is generation, is associated with him. For this reason they also call the Moon the mother of the world, and they think that she has a nature both male and female, as she is receptive and made pregnant by the Sun, but she herself in turn emits and disseminates into the air generative principles. For, as they believe, the destructive activity of Typhon does not always prevail, but oftentimes is overpowered by such generation and put in bonds, and then at a later time is again released and contends against Horus,⁴ who is the terrestrial universe ; and this is never completely exempt either from dissolution or from generation. [p. 107]