The symbol was designed in 1564 by John Dee, an English mathematician and occultist. Dee was educated at Cambridge and wrote extensively about mathematics, natural science, and astrology. He created this symbol, or monad, to represent the astrological shapes for the seven planets of Saturn, Jupiter, Mars, Venus, Mercury, the Moon, and the Sun. The body of the monad is based on the glyph for the planet Mercury, and contains the crescent, the circle, the dot, and the cross. These various shapes are derived from the zodiacal signs that are ruled by the planets mentioned above. Dee used this monad, and variations of it, to represent his research in the study of Alchemy.