The
pomerium or
pomoerium (
Latin, from
post +
moerium >
murum, "wall"), was the sacred boundary of the city of
Rome. In legal terms, Rome existed only within the
pomerium; everything beyond it was simply land belonging to Rome.
The pomerium was not a walled area (unlike the Chinese Forbidden City), but rather a legally and religiously defined one marked by cippi It encompassed neither the entire metropolitan area nor even all the proverbial Seven Hills (the Palatine Hill was within the pomerium, but the Capitoline and Aventine Hills were not). The Curia Hostilia and the well of the Comitia in the Forum Romanum, two extremely important locations in the government of the city-state and its empire, were located within the pomerium. The temple of Bellona was beyond the pomerium.
Weapons were also banned inside the pomerium for religious and traditional reasons. Praetorian guards were allowed in only in civilian dress (toga), and were then called collectively cohors togata. But it was possible to sneak in daggers (the proverbial weapon for political violence, see sicarius). Since Julius Caesar's assassination occurred outside this boundary, the senatorial conspirators could not be charged with blasphemy for carrying weapons inside the sacred city.