Marco Gobbi

In ancient times people could measure the time by the position of the sun, this was done by projecting a gnomon on a sundial that showed the time by the position of its shadow.
Two types of instruments existed for this purpose: sundials and solar clocks.

One of the largest sundials ever built was the ‘Horologium Augusti’, commissioned by Emperor Augustus in 9 B.C. in the center of Campus Martius in Rome. Within the same area of Campus Martius stood various works and monuments whose purpose was to glorify the figure of Augustus, unquestioned winner in the battle over the succession that arose after the death of Julius Caesar and now the sole Emperor.

The obelisk used as the gnomon for the clock came from the Egyptian city of Janu, whose inhabitants were devoted to the worship of the sun god, Ra; the city was also known by its Greek name of Heliopolis, the obelisks for the Egyptians in fact represented the petrified rays of the sun. 

Information about the working of the Clock has come down to the present day through the writings of Pliny the Elder, who also relates a curious anecdote; every September 23, the day of Augustus’s birthday, the shadow of the obelisk would lengthen until it projected its tip onto the entrance to the Ara Pacis (located to his right).

Currently, the Augustus clock no longer exists, but the obelisk and the Ara Pacis are still in Rome although placed in different and more distant locations. 

The sculpture, a 1:5 scale reconstruction of what the sundial on the Campus Martius was like, functions as a kind of shadow matrix, reinstating an event frozen in time.