Livy, Roman History, Books I-III
“ Those who regard only the etymology of the word, will have the pomerium to be a space of ground behind the walls: whereas it is rather a space on each side of the wall, which the Etruscans, in building cities, formerly consecrated by augury, within certain limits, both within and without, in the direction they intended to raise the wall: so that the houses might not be erected close to the walls on the inside, as people commonly unite them now, and also that there might be some space without left free from human occupation. ”
