Orologio di Augusto

The sundial of emperor Augustus consisted of a large travertine-paved trapezoid-shaped square on whose surface hours, seasons, months, and signs of the zodiac were indicated with bronze gilded letters. It was built in the area that currently stretches from Palazzo Montecitorio up to the Church of San Lorenzo in Lucina where some of its ruins can still be seen in the basements. The sundial was built in 10 BC as commemorated by the inscription situated at the base of the obelisk in Piazza Montecitorio that originally acted as gnomon of the sundial (the rod that projected its shadow on the square establishing the position of the sun and thus the time). The position of the sundial was connected with the Ara Pacis, towards which the shadow of the gnomon was pointed on Augustus’s birthday (September 23). Recent excavations have brought to light part of the surface in a basement in Via di Campo Marzio, but it probably belongs to a successive version that can be dated back to emperor Domitian, that shows the names of four signs of the zodiac (Virgo, Leo, Taurus, and Aries), the beginning of summer and the indication that "the Etesiae winds become calm" are written in Greek.