Uranus is the first planet discovered with a telescope, and in modern astrology it is treated as the ruler of Aquarius. It lies beyond Saturn, which for millennia marked the edge of the visible planetary order, and its discovery broke a boundary the classical glyph-making tradition had never had to cross: for the first time a planetary sign had to be invented rather than inherited from antiquity. Two rival proposals competed for decades before either stabilised.
The German astronomer Johann Gottfried Kohler suggested a symbol combining the signs for iron and gold, later refined by Johann Elert Bode, intended to represent the newly identified metal platinum, whose properties were then thought to combine those of the two older metals; this platinum glyph became the form generally preferred by astronomers.
A second, independent design instead built a monogram from a globe and an initial letter, and it was this rival sign, not the platinum symbol, that became the one most commonly used in astrological practice, a divide historians of astronomy trace to the differing needs of the two disciplines, astronomers favouring a sign tied to the discovery's chemistry, astrologers one tied to its discoverer.