Ave Roma Immortails, Volume 2 by F. Marion Crawford

In Italian, as in Latin, Ripa means the bank of a river, and the Twelfth Region took its name from being bounded by the river bank, from just below the island all the way to the Aurelian walls, which continue the boundary of the triangle on the south of Saint Sebastian's gate; the third side runs at first irregularly from the theatre of Marcellus to the foot of the Palatine, skirts the hill to the gas works at the north corner of the Circus Maximus, takes in the latter, and thence runs straight to the gate before mentioned. The Region includes the Aventine, Monte Testaccio, and the baths of Caracalla. The origin of the device, like that of several others, seems to be lost.

The Aventine, ever since the auguries of Remus, has been especially the refuge of opposition, and more especially, perhaps, of religious opposition. In very early times it was especially the hill of the plebeians, who frequently retired to its heights in their difficulties with the patricians, as they had once withdrawn to the more distant Mons Sacer in the Campagna. The temple of Ceres stood in the immediate neighbourhood of the Circus, on the line of approach to the Aventine, and contained the archives of the plebeian AEdiles. In the times of the Decemvirs, much of the land on the hill was distributed among the people, who probably lived within the city, but went out daily to cultivate their little farms, just as the inhabitants of the hill villages do today.