Sunday, May 24, 2015



594/589 BC, erected for Psammetichus II at Heliopolis in Egypt

It was transported to Rome by order of Augustus (27 BC/14) who placed it in 10 BC in a square of about 160 x 75 m (525 x 246 feet) in the Campus Martius (north of Parliament Square) as the sundial gnomon

It measures 22 meters (72 feet)
With base and globe with papal coat of arms it measures 29 m (95 feet)

Augustus took the advice of astronomers and mathematicians from Alexandria including Facondo Novio

It was an instrument for measuring time located on a square divided into a pattern of bronze rules, but also a monument to the sun, to the stars and to the golden Augustan aetas, the golden age of Augustus
It fell in the ninth century and it was restored in 1792 with pieces from the Column of Antoninus Pius (138/161) of red granite and moved in Piazza Montecitorio by Giovanni Antinori (1734/92) at the behest of Pius VI Braschi (1775/99)

The Column of Antoninus Pius had been accidentally destroyed during the transport organized by Francesco Fontana in 1705 from the nearby garden of monks in which it had been found in Piazza Montecitorio

In 1998, a renovation of the square by Franco Zagari (1945) reinstated the visibility of the sundial

“The elegant topography is reconstructed as it was before the change made by Ernesto Basile at the beginning of the century, reconstructing a 'peacock's tail' similar to the original by Carlo Fontana, the point of culmination of an upward momentum of no less than four meters from the back of the piazza to the entrance of the building (part of the 'monte'). This reintroduces a counter-movement to the curvature of the palace by Bernini and Fontana, which is the essential key of the Baroque conception of the square. The project makes visible the sophisticated reuse of the obelisk as a sundial (...): a line on the ground allows to read the 'true noon' (astronomical), when sunlight passes through a hole of the spheroid on the top and makes a hole of light in the shadow on the ground” (Franco Zagari Web Site -

An inscription on the base of the obelisk erroneously attributes it to Pharaoh Sesostris

There are two other Augustan inscriptions: the conquest of Egypt, and the dedication to the sun
Every September 23, the birthday of Augustus, the shadow of the tip coincided with the entry of the Ara Pacis

Every April 21, the birthday of Rome, one of the sides of the obelisk perfectly aligned with the rising sun

No comments:

Post a Comment