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.

I, Porta Capena, so called from the gate in the Servian wall, an irregularly shaped district, beginning at the east corner of the Palatine, bounded on the west by that hill, and running south to some distance beyond the porta Capena between two lines not more than 150 meters apart on the average. Beyond the Aventine it widened considerably and extended to the bank of the Almo, some distance beyond the Aurelian wall. It is possible that Regions I, II, III, IV, and X all met at one point near the Meta Sudans.

The Porta Capena's gate. A gate in the Servian wall on the south-west slope of the Caelian. It was near the grove of the Camenae, and from it the via Appia issued (Liv. i. 26. 2; iii. 22. 4; Serv. Aen. vii. 697; Frontinus, aq. i. 5, 19; Ov. Fast. iv. 343; v. 673; vi. 192; Dionys. viii. 4; Fest. 110, 115, 347). The ancient derivation of the name from the Etruscan Capena (Serv. loc. cit.) is highly improbable, and no satisfactory explanation has been found (Jord. i. I. 270-271). The discovery of several portions of the wall in 1867-1868, and of what is probably a pier of the gate itself during the recent construction of the Passeggiata archeologica, has definitely established its location (see Jord. i. I. 228; Gilb. ii. 293, for references to the literature of earlier excavations; NS 1909, 427; BC 1908, 109-150; Bartoli, Rassegna Cont. iii. No. 2, 1910, 19 ; T ix. 19). Domitian is said to have restored the porta Capena (Chron. 146), but as a mere gateway would have had no meaning then, the restoration was probably in connection with the extension of the aqua Marcia, which was brought across the Caelian by a branch, the rivus Herculaneus, and ended supra portam Capenam (Frontinus i. 19). This aqueduct was at too low a level to have crossed to the Aventine; but there was another and higher branch which crossed the gateway, as is clear from references in literature (Frontinus ii. 76-the Caelian and Aventine priusquam Claudia perduceretur, utebantur Marcia et Iulia; Mart. iii. 47; Iuv. iii. 11 and Schol.). The latest investigation, however, of the remains of the arches of this branch shows them to be of the time of Nero.