Libra the Scales, located between Virgo and Scorpio, can be traced back to the Sumerians of around 2000 BC which called the constellation the 'Balance of Heaven', maybe because that time the autumnal equinox could be found there, one of the two days in the year where night and day were of equal length.

The ancient Egyptians also saw a pair of scales in Libra and associated it to the scales of Anubis, the jackal-headed god of the dead. Anubis was the one leading the souls of the dead to the underworld, but he judged the souls by what they had done in life. He would place the heart of the deceased on one scale and weight it against the Feather of Truth which was provided by Maat, the goddess of truth. If the deceased has been good his heart would be light and equal to the feather, and Anubis would send the soul to the kingdom of Osiris. If the heart was loaded by sins it would weight more than the feather, and the soul was lost forever.

Anubis was an objective god, honorful but merciless, a symbol of justice and final judgement of which no-one could escape. The scales were his attribute, and in the sky two stars of Libra, known today as Sigma Librae and Zubenelgenubi, were the gate where all the planets including sun and moon had to pass through on their way across the ecliptic.

The Greeks did not see any scales in Libra but regarded it as a part of Scorpio which they called 'Chelae', the 'claws', which is the reason why Libra is the only sign in the zodiac not associated to a person or animal of Greek mythology. Arab astronomers followed the Greek and gave two of Libra's stars their names: Zubenelgenubi which means 'southern claw' and Zubeneschamali which translates as 'northern claw'.

The Romans saw Libra as an independent constellation again from about 100 BC, associating it once more to scales as a symbol of justice. For them, the scales where held by Justitia (Astraea or Dike), the goddess of justice. Like anubis, she judged the souls of the deceased by weighing them in their balance.