The use of dual rulerships in a manner such as this was also be known as "co-rulership". Some astrologers believed that the new co-rulers were primary rulers of the signs with which they were associated and might have been sole rulers of those signs, and if that was the case, two other planets, one linked to Libra or Taurus, and the other to Virgo or Gemini, may await discovery, thus eliminating the need for dual rulership of a sign. Although the status of Ceres has not been conclusively decided at the moment in astrology, it has been suggested as the ruler of Virgo or Taurus. For some modern astrologers including many European astrologers, it is the ruling planet of Virgo based upon observation of its role in synastric charts. Significantly, the generation of astrologers who first encountered Ceres in the early 19th century after its discovery, before its demotion to an asteroid in the middle of the 19th century, assigned it rulership of Virgo. For a minority of astrologers, it is the ruling planet of Taurus along with Venus. The possibility exists that it isn't involved with any sign, but in any event, it can almost definitely be attributed to the Earth element.
