Sagittarius is ruled by Jupiter. Common associations are the colour royal blue, and the number 3. It rules the hips, thighs, and sciatic nerve in the physical body. Its zodiac symbol is the centaur. The sign is connected to expanding horizons both metaphorical and physical. Its keywords are I see.
What can I say about Sagittarius? I don't know who it was that decided Leos were the performers of the zodiac because I've found that if anyone has to have the focus on them, it's the good ol' Sag. It doesn't matter whether they are climbing Mount Everest or washing up they want the same amount of applause for, well, just being great really. Where Leo will confess to having God as his father, the Sagittarian will claim to be God himself. It is almost impossible to insult them if you're just being honest and for those who have many planets in Sag, you will notice they never keep their legs still. That's not to say they won't sit on their arses all day; it's just their legs will keep on moving. They don't exhibit the impulsive action of Aries, I've found their temperament to be more like horses in the starting block. For someone who will profusely express they are not vain or remotely moved by appearance they spend an awful lot of time checking themselves out in the mirror, they look to the left, to the right and back to the left again and never seem to tire of seeing the great one.
Amongst their good traits, they are enormous fun to be around and can be the life and soul of the party. It doesn't matter what you're talking about they will try to understand where you're coming from and if it's a subject they know nothing about they won't switch off with a clueless expression. Instead, they'll ask questions and engage with you. Broad-mindedness is often apparent, and I'm sure it must have been a Sag who quoted "to each his own". Because we are dealing with a mutable sign, philosophies and views can change direction with the wind, yet this seems to increase their ability to get along with nearly everyone. They can have friends from all walks of life and will chat happily to strange old people on the bus. Traditionally it is said you can't tie them down which is true, but at the same time, they can offer loyalty. They really are like horses; they can be tamed but need freedom to roam outside. They need to be able to keep hold of their inner spirit which is the same for all fire signs. It's a bit like having a compartment in which you store a part of yourself which never gets shared with anybody, and what's more, you're going into dangerous territory if you try to cross those boundaries...you're likely to see nothing but their back end.
Wherever Sag is in the birth chart freedom to explore is needed. Mercury here gives strong telepathy and a need to pursue higher levels study. Jupiter will strengthen the sense of spirit significantly, and Saturn here will either restrict activities or demand solid structures be built around philosophy and religion.