A Treatise on Astrology, Liber 536 by Aleister Crowley, 1917

Neptune in the Zodiacal Signs

The influence of the zodiacal sign upon Neptune operates only in a limited manner. As Neptune takes fifteen years or so to pass through a sign, generalisations must be observed. Were we to say ‘Neptune in Aries indicates the martial temperament’, it could be translated ‘All persons born between 1861 and 1875 have the martial temperament’; but where we are considering the modification of some other planets by an aspect of Neptune, it is clear that there will be a difference between the action of Neptune when he is in Aries and when he is in Taurus. His characteristic as the Zeitgeist will act and that most efficiently upon the other planets.

We shall now proceed to a study of the action of the signs upon Neptune, asking the reader to bear this limitation carefully in mind.