Zodiac Signs History: From Babylonian Astronomy to Hellenistic Astrology

The twelve signs of the Western zodiac are older than astrology as we know it. They began as a tool of Babylonian astronomy, a way of dividing the Sun's yearly path into twelve equal parts, and were turned into a system for reading character and fate by astrologers in the Hellenistic world. This guide explains how that happened, and sets out the signs.

A Babylonian invention

Babylonian astronomers tracked the Moon and planets against the band of stars along the ecliptic, the Sun's apparent path. By around the fifth century BC they had divided it into twelve equal sections of thirty degrees, each named after a constellation. Several of the figures are recognisably Babylonian: the sea-goat that became Capricorn, and "the Furrow", the ear of grain of the goddess Šala, which became Virgo.

Hellenistic astrology

After Alexander's conquests, Greek-speaking scholars, above all in Egypt, combined Babylonian observation with Greek mathematics and philosophy and with Egyptian star lore. The result was horoscopic astrology, in which the positions of the planets in the twelve signs at the moment of birth were used to interpret a person's life. Ptolemy's Tetrabiblos, written in the second century AD, became its most influential textbook.

Signs are not constellations

A zodiac sign is a thirty-degree section of the sky measured from the spring equinox; a constellation is a group of stars of varying size. Because the Earth's axis slowly wobbles, the signs used in Western astrology have drifted away from the constellations that gave them their names, which is why the Sun is usually in the constellation Pisces, not Aries, at the spring equinox today.

The twelve signs

| Sign | Symbol | Figure | Approximate dates | |---|---|---|---| | Aries | ♈ | Ram | 21 March – 19 April | | Taurus | ♉ | Bull | 20 April – 20 May | | Gemini | ♊ | Twins | 21 May – 20 June | | Cancer | ♋ | Crab | 21 June – 22 July | | Leo | ♌ | Lion | 23 July – 22 August | | Virgo | ♍ | Maiden | 23 August – 22 September | | Libra | ♎ | Scales | 23 September – 22 October | | Scorpio | ♏ | Scorpion | 23 October – 21 November | | Sagittarius | ♐ | Archer | 22 November – 21 December | | Capricorn | ♑ | Sea-goat | 22 December – 19 January | | Aquarius | ♒ | Water-bearer | 20 January – 18 February | | Pisces | ♓ | Fishes | 19 February – 20 March |

The dates are approximate and shift by a day in some years.

Newer symbols

The traditional zodiac knew only the Sun, Moon and five visible planets. Later discoveries have gained their own astrological glyphs, such as Ceres and the dwarf planet Eris. For one sign in depth, see Aquarius.

Zodiac jewellery

A zodiac sign is one of the most personal symbols to wear. AURYN's zodiac designs can be found in the necklaces and charms collections.