Does Chiron rule the star sign Virgo?
The question keeps coming up: which star sign does Chiron rule, and is it Virgo? The short answer is: none — and Virgo least of all. The long answer is the more interesting one, because it shows how a rulership comes about in the first place. It is not settled by decision; it follows from an arrangement.
How the twelve signs were handed out
The assignment of planets to signs looks like a list to be learnt by heart. In fact it is built, out of a single starting point.
The two lights each receive one sign: the Moon Cancer, the Sun Leo. The two of them lie side by side in the circle, and from their shared boundary the series runs outwards in both directions, ordered by how long the five other planets take to complete one circuit — from the fastest to the slowest. On the Leo side: Mercury Virgo, Venus Libra, Mars Scorpio, Jupiter Sagittarius, Saturn Capricorn. On the Cancer side the same sequence in the opposite direction: Mercury Gemini, Venus Taurus, Mars Aries, Jupiter Pisces, Saturn Aquarius.
Twelve signs, seven planets: each of those five gets two signs, the two lights one each, and the whole thing stands as a mirror image. Nothing is left over. An eighth body could only have a rulership if something were taken away from one of the seven. That is exactly what modern astrology did: after their discovery, Uranus, Neptune and Pluto were each given a sign, and the old rulers moved into second place there.
Why Virgo is the least promising candidate
Virgo of all signs has the least room. In it two things fall on the same planet: Mercury rules the sign, and it also has its exaltation there. No other sign shows this doubling.
Anyone who wants to award Virgo to Chiron therefore has to dislodge Mercury from a doubly secured position. What hangs on that shows up when a chart is read: through the ruler of a sign, a whole area of life is tied to a planet. Swap the ruler and it is not a detail that changes, it is the way several houses are read. How this web hangs together is set out under Planets.
Where the suggestion comes from
It is tempting all the same, and the reason lies in plain sight. Virgo counts as the sign of checking and of keeping things in repair; illness and the healing arts have been at home in this region of the chart since antiquity. Chiron, in turn, has been associated mainly with injury and healing ever since it was found. Two themes resemble each other, so they are put together.
This is exactly where mistrust pays. A resemblance between two meanings is easily found; with enough indulgence it can be found between almost anything. The result is correspondingly uneven: the same way of arguing leads other authors to Sagittarius, and besides Chiron other celestial bodies have been proposed for Virgo. Where two suggestions are equally well founded and nothing decides between them, there is no result, only a taste.
What Chiron is astronomically
A small body, found in 1977, travelling in the region between Saturn and Uranus. It does not sort neatly into a class: it was recorded as a minor planet, but it also shows the behaviour of a comet. Something of consequence hangs on this. An order written down some two thousand years ago cannot have provided anything for a body found only in 1977; at most it can grant it something after the fact.
What you can do instead
Anyone who wants to work with Chiron needs no rulership for it. Where it sits in the birth chart and which planets it is connected with there can be read off anyway. A test is quickly made: read a chart once with it and once without. If the reading stays the same, it has contributed nothing; if it turns into a different one, you can name what made the difference.
And if what actually interests you is Virgo and not Chiron: what makes this sign what it is hangs on Mercury — on where it stands, its condition and its house in the birth chart. The sign itself is described in the series of the twelve, under Zodiac signs.