Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
A remarkable memorial of the distinction between these two portions of the city was preserved in one of the oldest sacred customs of the later Rome, the sacrifice of the October horse yearly offered in the -Campus Martius-: down to a late period a struggle took place at this festival for the horse's head between the men of the Subura and those of the Via Sacra, and according as victory lay with the former or with the latter, the head was nailed either to the Mamilian Tower (site unknown) in the Subura, or to the king's palace under the Palatine. It was the two halves of the old city that thus competed with each other on equal terms. At that time, accordingly, the Esquiliae (which name strictly used is exclusive of the Carinae) were in reality what they were called, the "outer buildings" (-exquiliae-, like -inquilinus-, from -colere-) or suburb: this became the third region in the later city division, and it was always held in inferior consideration as compared with the Suburan and Palatine regions.
Other neighbouring heights also, such as the Capitol and the Aventine, may probably have been occupied by the community of the Seven Mounts; the "bridge of piles" in particular (-pons sublicius-), thrown over the natural pier of the island in the Tiber, must have existed even then--the pontifical college alone is sufficient evidence of this--and the -tete de pont- on the Etruscan bank, the height of the Janiculum, would not be left unoccupied; but the community had not as yet brought either within the circuit of its fortifications. The regulation which was adhered to as a ritual rule down to the latest times, that the bridge should be composed simply of wood without iron, manifestly shows that in its original practical use it was to be merely a flying bridge, which must be capable of being easily at any time broken off or burnt. We recognize in this circumstance how insecure for a long time and liable to interruption was the command of the passage of the river on the part of the Roman community.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/1-04-beginnings-rome.asp?pg=13