The numbers, the orders, the Hierarchies, declare the glory of the movable Heavens, which are nine; and the tenth announces this Unity and stability of God.

And therefore the Psalmist says: "The Heavens declare the glory of God, and the Firmament showeth His handiwork." Wherefore it is reasonable to believe that the movers of the Heaven of the Moon are of the order of the Angels, and those of Mercury may be the Archangels, and those of Venus may be the Thrones, in whom the Love of the Holy Spirit being innate, they do their work conformably to it, which means that the revolution of that Heaven is full of Love.
The form of the said Heaven takes from this a virtue by whose glow souls here below are kindled to love according to their disposition.
And because the ancients perceived that Heaven to be here below the cause of Love, they said that Love was the son of Venus, as Virgil testifies in the first book of the AEneid, where Venus says to Love: "Oh! son, my virtue, son of the great Father, who takest no heed of the darts of Typhoeus." And Ovid so testifies in the fifth book of his Metamorphoses, when he says that Venus said to Love: "Son, my arms, my power." And there are Thrones which are ordered to the government of this Heaven in number not great, concerning which the Philosophers and the Astrologers have thought differently, according as they held different opinions concerning its revolutions.

But all may be agreed, as many are, in this, as to how many movements it makes.

Of this, as abbreviated in the book of the Aggregation of the Stars, you may find in the better demonstration of the Astrologers that there are three: one, according as the star moves towards its Epicycle; the other, according as the Epicycle moves with its whole Heaven equally with that of the Sun; the third, according as the whole of that Heaven moves, following the movement of the starry sphere from West to East in one hundred years one degree.

So that to these Three Movements there are Three Movers.