Obv "NERO CAESAR AVG GERM IMP"
Bare bust right
Rev "PACE P R VBIQ PARTA IANVM CLVSIT SC"
Temple of Janus with doors closed
There is a series of well known sestertii, dopondii and asses issued by Nero that show the Temple of Janus with closed doors. It is also widely known that the closing of the door was symbolic of peace throughout the Roman Empire. But, what is not widely known is why the doors being shut came to represent peace........
Hill's Monuments of Rome as Coin Types (1989) offers some suggestions as to where the temple was located but does not provide an answer to our question. Similarly Stevenson's Dictionary of Roman Coins (1889) can offer us that Livy tells us that the doors were mostly open, in fact were shut only once, from the foundation of Rome to the battle of Actium, but again not why they should be shut. Suetonius reckons that Nero's closing was the third occasion on which the doors were shut.
The answer, however, does appear in Donaldson's Architectura Numismatica (1859). In it he tells us that, according to legend, the original Temple of Janus was built by either Quirinus or Romulus. He notes that, according to the ancient writer Macrobius, during the Sabine wars the enemy were rushing into Rome through the Porta Janualis when they were overwhelmed by a vast torrent of boiling water which impetuously flowed from the Temple of Janus. From then it was decreed that as Janus had come to their help during a time of war the doors should remain open.