In mythology Libra is related to the Greek Goddess of Justice , Themis , the Greek mythology version of Atalanta ( meaning balanced ) , and Astraea ( daughter of Themis ) , who went up to heaven and became the constellation of Virgo ( astrology , and carried the scales of justice , which is the constellation Libra . The symbol for Libra is the Scales . In Roman mythology , Libra is considered to depict the scales held by Astraea ( identified as Virgo ) , the goddess of justice .