Modern Rulership

After Uranus, Neptune and Pluto were discovered, astrologers assigned each to the sign that seemed to match its character: Uranus to Aquarius, Neptune to Pisces, Pluto to Scorpio. Those signs keep their traditional rulers as well, so Aquarius is read through Saturn and Uranus, Pisces through Jupiter and Neptune, and Scorpio through Mars and Pluto. Both systems are in current use and neither has displaced the other. The practical approach is to read the traditional ruler first, since the whole dignity scheme depends on it, then take the modern ruler as a second layer of detail.