The Roman Pomerium

https://en.wikipedia.org/wiki/Pomerium

“The term is a classical contraction of the Latin phrase post moerium, literally “beyond the wall”. The Roman historian Livy writes in his Ab Urbe Condita that, although the etymology implies a meaning referring to a single side of the wall, the pomerium was originally an area of ground on both sides of city walls. He states that it was an Etruscan tradition to consecrate this area by augury and that it was technically unlawful to inhabit or to farm the area of the pomerium, which in part had the purpose of preventing buildings from being erected close to the wall (although he writes that, in his time, houses were in fact built against the wall on the line).[1]”