At the four corners of her throne stand the four human virtues, Prudence, Temperance, Justice, and Fortitude, distinguished less by beauty of shape than by determined energy of symbolism.

Temperance is a naked woman, with hair twisted in the knots and curls of a Greek Aphrodite.

Justice is old and wrinkled, clothed with massive drapery, and holding in her hand the scales.

Throughout this group there is no attempt to realise forms pleasing to the eye; the sculptor has aimed at suggesting to the mind as many points of intellectual significance as possible.

In spite of ugliness and hardness, the "Allegory of Pisa" commands respect by vigour of conception, and rivets attention by force of execution.
A more popular and pleasing monument by Giovanni Pisano is the tomb of Benedict XI.