Upon the completion of the census, which had been expedited by fear of a law that threatened with death and imprisonment those who failed to register, Servius issued a proclamation calling on all Roman citizens, both horse and foot, to assemble at daybreak, each in his own century, in the Campus Martius.
There the whole army was drawn up, and a sacrifice of a pig, a sheep, and a bull was offered by the king for its purification. This was termed the “closing of the lustrum,” because it was the last act in the enrolment. Eighty thousand citizens are said to have been registered in that census; the most ancient of the historians, Fabius Pictor, adds that this was the number of those capable of bearing arms.
To meet the wants of this population it was apparent that the City must expand, and so the king added two hills, the Quirinal and the Viminal, after which he proceeded to enlarge the Esquiline,1
going there to live himself, that the place might obtain a good reputation. He surrounded the City with a rampart, trenches, and a wall, and so extended the “pomerium.”
This word is interpreted by those who look only at its etymology as meaning “the tract behind the wall,” but it signifies rather “the tract on both sides of the wall,” the space which the Etruscans used formerly to consecrate with augural [p. 157]
ceremonies, where they proposed to erect their wall,2
establishing definite limits on either side of it, so that they might at the same time keep the walls free on their inward face from contact with buildings, which now, as a rule, are actually joined to them, and on the outside keep a certain area free from human uses.
This space, which the gods forbade men to inhabit or to till, was called “pomerium” by the Romans, quite as much because the wall stood behind it as because it stood behind the wall; and as the city grew, these consecrated limits were always pushed out for as great a distance as the walls themselves were to be advanced.3