← Encyclopedia of Astrology · lesson 219/235
Great conjunctions
What it is
Jupiter goes round the zodiac in about twelve years, Saturn in about twenty-nine and a half. Jupiter catches Saturn up roughly every twenty years (19.86 on average), and each meeting is a great conjunction. They are the slowest meetings of the planets the ancients could see, and so the medieval astrologers took them as the clock of history: of dynasties, peoples, laws and, in the more daring claims, religions.
The doctrine is Persian and Arabic rather than Greek. Ptolemy does not use it; Māshāʾallāh wrote on it, and Abū Maʿshar's Book of Religions and Dynasties, usually called On the Great Conjunctions, made it the centre of mundane astrology for the next seven hundred years.
The rhythm through the elements
Each conjunction falls about 243° on from the last — about a trine short of a full circle — so three meetings in a row land roughly a trine apart, in signs of the same element (triplicity). Because the trine is not exact, the meetings drift slowly, and after about two centuries they move into the next element. That move, the "shift" or mutation, was read as a turn of an age; the full round through all four elements takes most of a millennium, the exact figure depending on the author.
The series of our own time:
| Date | Position | Element |
|---|---|---|
| 1842 | 9° Capricorn | earth |
| 1861 | 18° Virgo | earth |
| 1881 | 2° Taurus | earth |
| 1901 | 14° Capricorn | earth |
| 1921 | 27° Virgo | earth |
| 1940–41 | 9°–14° Taurus | earth |
| 1961 | 25° Capricorn | earth |
| 1980–81 | 5°–10° Libra | air |
| 2000 | 23° Taurus | earth |
| 21 December 2020 | 0°29′ Aquarius | air |
| 2040 | 18° Libra | air |
| 2060 | 1° Gemini | air |
The earth series ran for well over a century. The 1980–81 meeting in Libra was an early glimpse of air; the 2000 meeting fell back into earth; and in December 2020 the conjunction entered Aquarius, opening a run of air meetings expected to last about two hundred years. Many astrologers read that shift in the language of the elements — from matter and possessions towards ideas, networks and exchange. It is a picture of the weather of an age, and it inclines; it cannot say what any particular person or country will make of it.
How it was read
Abū Maʿshar worked at several scales: the single twenty-year conjunction, cast for the moment it is exact, and judged with the chart of the Sun's ingress into Aries in that year; the series in one element; the full round; and longer still, the "world-years" of his Book of Thousands. The sign of a conjunction, its planets' dignity, and the house it falls in for a given city were all weighed.
The doctrine was argued over from the start. Astrologers who followed Ptolemy preferred to judge the year from eclipses and lunations, and Church writers condemned the claim that the conjunctions announced new prophets or faiths. Read as a calendar of collective seasons, it remains one of the most widely used tools of world astrology.