The Divine Institutes

But some one will say that these things are feigned by the poets. This is not the usage of the poets, to feign in such a manner that you fabricate the whole, but so that you cover the actions themselves with a figure, and, as it were, with a variegated veil. Poetic licence has this limit, not that it may invent the whole, which is the part of one who is false and senseless, but that it may change something consistently with reason. They said that Jupiter changed himself into a shower of gold, that he might deceive Danae. What is a shower of gold? Plainly golden coins, by offering a great quantity of which, and pouring them into her bosom, he corrupted the frailty of her virgin soul by this bribe. Thus also they speak of a shower of iron, when they wish to signify a multitude of javelins. He carried off his catamite upon an eagle. What is the eagle? Truly a legion, since the figure of this animal is the standard of the legion. He carried Europa across the sea on a bull. What is the bull? Clearly a ship, which had its tutelary image fashioned in the shape of a bull. So assuredly the daughter of Inachus was not turned into a cow, nor as such did she swim across, but she escaped the anger of Juno in a ship which had the form of a cow. Lastly, when she had been conveyed to Egypt, she became Isis, whose voyage is celebrated on a fixed day, in memory of her flight.