Samuel Ball Platner, A Topographical Dictionary of Ancient Rome, London: Oxford University Press, 1929.

Because of Augustus, there were 14 regions in the city of Rome compared to its previous 4. This division into fourteen regions continued in force until the sevent century when an ecclesiastical division into seven regions was introduced and opened the way for the entirely different organization of the Middle Ages.

VI, Alta Semita. It was so called from a street that followed the ridge of the Quirinal, like the present Via Venti Settembre. Bounded on the south and south-west by Region IV it originally included the Quirinal from the imperial fora to the Servian wall between the porta Viminalis and the porta Collina, and extended far enough west to take in the horti Sallustiani, and north beyond the line of the Aurelian wall. In the fourth century, after the castra Praetoria had been made a part of the city, the boundary of this region coincided with the Aurelian wall from the porta Salaria south round the castra. From a point a little west of the porta Pinciana, the boundary ran almost due south to the forum of Trajan.

ALTA SEMITA: the name given in the Regionary Catalogue to the sixth region of Augustus. This lay between the imperial fora, the east boundary of Region VII, and the north-west boundary of Region IV, and included the Viminal, the Quirinal, the valley between the Quirinal and the Pincian, and the lower slope of the latter hill. This region took its name from that of its principal street, the Alta Semita, which ran north-east along the ridge of the Quirinal to the porta Collina, corresponding with the modern Via del Quirinale and Via Venti Settembre from the Piazza del Quirinale eastward. The north-eastern part of this street was probably called VICUS PORTAE COLLINAE (q.v.), if we may infer this from an inscription (CIL vi.450) found near S. Susanna (Jord. i.1.510). The ancient pavement lies at an average depth of 1.83 metres below the present level (HJ 418; BC 1889, 332; RhM 1894, 387; Mitt. 1892, 312).