Plin. Hist. Natur. iii. 5 [ 9]. To confirm our idea, we may observe that for a long time Mount Caelius was a grove of oaks, and Mount Viminal was overrun with osiers; that in the fourth century the Aventine was a vacant and solitary retirement; that till the time of Augustus the Esquiline was an unwholesome burying-ground; and that the numerous inequalities remarked by the ancients in the Quirinal sufficiently prove that it was not covered with buildings. Of the seven hills, the Capitoline and Palatine only, with the adjacent valleys, were the primitive habitation of the Roman people. But this subject would require a dissertation.