Sagittarius

The Eleventh Doctor once said to Solomon, the he was probably a Sagittarius. (TV: Dinosaurs on a Spaceship)

In 2009, the "Children of Sagittarius" were the sixth to be brought under the control of the Ancient Lights when Martin Trueman invoked the sign into his circle. Sagittarius followed Scorpio and preceeded Capricorn. (TV: Secrets of the Stars)

Behind the scenes
Sagittarius is one of the seven signs of the Zodiac, which roughly falls under the Gregorian calendar dates of approximately 23 November through to 22 December. The Doctor claiming to be a sagittarius is a reference to the first ever episode of Doctor Who, An Unearthly Child, airing on 23 November 1963.