Prudence

Prudence has a serpent wound around her arm and holds a mirror in her hand.

Additional information:
Prudence is one of the cardinal virtues. She holds a mirror so that she can see her true face, because a reflection cannot lie. The serpent is an allusion to a passage in the Gospel of Matthew where Christ tells his followers to be as wise as serpents. The city fathers wanted to convey that they managed civic affairs wisely.