Horologium of Augustus

• The Horologium of Augustus, also known as the Solarium Augusti, was a giant sundial in Rome which used an Obelisk for citizens to tell the time.

History

• In 10 BCE Augustus built a giant clock, the ‘Solarium Augusti’, in the Campus Martius in Rome.
• It was constructed using the Obelisk of Montecitorio, now in the Piazza de Montecitorio, Rome, to cast a shadow to tell the time.
• On the 23rd September, Augustus’ birthday, the shadow fell on the altar of the Ara Pacis, the altar of the Goddess of Peace.

The Site today

• The Obelisk of Montecitorio, can now be seen in the Piazza de Montecitorio, Rome.

Obelisk of Montecitorio, Rome