The concept of Lady Justice is very old, dating back to ancient Greek and Egyptian times.
Themis was Greek goddess of justice, law, order, and good counsel. Themis uses the scales of justice to always remain balanced and pragmatic.
Ancient Egyptians had Ma’at of the Old Kingdom, who represented order and justice carried with her a sword and the Feather of Truth.
However, the modern concept of Lady Justice is most similar to the Roman goddess Justitia. Justitia has become the ultimate symbol of justice in Western civilization. In Roman art, Justitia is often depicted with the sword and scales alongside her sister Prudentia who holds a mirror and a snake.