concerning planetary cycles and ages.
this is info from 'esoteric astrology' by alice bailey (1940)

there are three cycles that the sun passes through the zodiac:

1. The succession of the greater rounds of the zodiac or a period of cycles of approximately 250,000 years has a correspondence to the life cycle of the Monad.
2. The progress of the Sun as it passes through the signs in the zodiac during one of these 25,000 year cycles finds its analogy in the life cycle of the ego or soul.
3. The lesser zodiac covered—from the angle of extreme illusion—in the course of one year, corresponds to the life of the personality

furthermore, it is said that the last 250.000 round ended when the sun entered pisces 2000 years ago.
and that aquarius will rule both the next greater cycle of 25.000 years and the sun will be for the next 2300 years in aquarius:

"This is, therefore, the most amazing period in the history of humanity. Added to this, it must be borne in mind that we are entering another greater round of the Zodiac, and this coincides with the lesser zodiacal activity because Aquarius governs the greater immediate cycle of 25,000 years and is also the sign into which the sun is now moving for a period of 2300 years—a most amazing happening and full of import in our planetary history;"