The Palatine was the original seat of the Roman community, the oldest and originally the only ring-wall.  The urban settlement, however, began at Rome as well as elsewhere not within, but under the protection of, the stronghold; and the oldest settlements with which we are acquainted, and which afterwards formed the first and second regions in the Servian division of the city, lay in a circle round the Palatine.  These included the settlement on the declivity of the Cermalus with the “street of the Tuscans”—­a name in which there may have been preserved a reminiscence of the commercial intercourse between the Caerites and Romans already perhaps carried on with vigour in the Palatine city—­and the settlement on the Velia; both of which subsequently along with the stronghold-hill itself constituted one region in the Servian city.  Further, there were the component elements of the subsequent second region—­the suburb on the Caelian, which probably embraced only its extreme point above the Colosseum; that on the Carinae, the spur which projects from the Esquiline towards the Palatine; and, lastly, the valley and outwork of the Subura, from which the whole region received its name.  These two regions jointly constituted the incipient city; and the Suburan district of it, which extended at the base of the stronghold, nearly from the Arch of Constantine to S. Pietro in Vincoli, and over the valley beneath, appears to have been more considerable and perhaps older than the settlements incorporated by the Servian arrangement in the Palatine district, because in the order of the regions the former takes precedence of the latter.  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