Temple of Janus (Roman Forum)
In ancient Rome, the main Temple of Janus stood in the Roman Forum. It had doors on both ends, and inside was a statue of Janus, the two-faced god of boundaries. The Temple doors (the "Gates of Janus") were closed in times of peace and opened in times of war.
The closing of the Temple doors was a very rare event. It is said to have happened for the first time under King Numa Pompilius (715-673 BC), for the second time under Titus Manlius in 235 BC, three more times by Augustus in 29 BC, 25 BC, and possibly 13 BC a sixth time by Nero in 66 AD and a seventh time under Vespasian in AD 70. It is likely that Trajan and Hadrian and Antoninus Pius each closed the Gates of Janus once.
Plutarch, in Life of King Numa, wrote:
[Janus] also has a temple at Rome with double doors, which they call the gates of war; for the temple always stands open in time of war, but is closed when peace has come. The latter was a difficult matter, and it rarely happened, since the realm was always engaged in some war, as its increasing size brought it into collision with the barbarous nations which encompassed it round about. But in the time of Augustus it was closed, after he had overthrown Mark Antony; and before that, when Marcus Atilius and Titus Manlius were consuls, it was closed a short time; then war broke out again at once, and it was opened.
The Res Gestae Divi Augusti, a first person account of the life of Augustus, claims:
Janus Quirinus, which our ancestors wished to be closed whenever peace had been secured by victories throughout the Roman empire by land and sea, was recorded to have been closed, before I was born, twice altogether since the foundation of the city, but the senate decreed that it should be closed on three occasions while I was princeps.
- Pax Romana