In ancient ethnography and history there occur numbers, which, in a surprising manner, recur at the most different periods; they are by no means fanciful; to regard them as something mystical, is itself a strange fancy, though there have been men of great intelligence, who have not been able to resist this notion. The number seven which so often meets us in Roman history, is something peculiar which has taken deep root there. There are unmistakeable traces that, previous to the complete union between the Romans and Quirites, Roma on the Palatine, Lucerum on the Caelius, and the town on the Aventine, together with their suburbs, formed one community, which was divided into seven districts, and bore the name of _Septimontium_. These seven hills were afterwards transferred to the whole of the city of Rome. Every one knows the passage in Virgil, _Septemque una sibi muro circumdedit arces_; but these are in part quite different hills from those originally comprised under the name Septimontium, which did not even consist of seven distinct hills.[6] They then were, the Palatine, Capitoline (formerly called Tarpeius), Quirinal, Viminal, Esquiline, Caelius, and Aventine. In this sense, and when all were enclosed by one wall, the Aventine also is reckoned as one of the seven hills, though otherwise it is not always regarded as a part of the city. In order not to go beyond the number seven, two very distinct hills, the Cispius and Oppius, were treated as one under the name Esquiline; the Aventine, at least in the opinion of the Romans, was the highest and most considerable of all; in order, therefore, not to leave it out, the two mentioned before were united into one. They can still be clearly distinguished, however much the forms of the hills have otherwise become obscured by ruins and rubbish: even the most indifferent observer will recognise them as two hills.