Livy 1.8

With divine matters having been attended to by rite and the multitude, which was able to gather into the body of one people by nothing except by laws, having been called to council, (Romulus) gave laws, which he thought (supply est) would be thus holy for a rough race of men if he himself had made himself venerable by symbols of power, he made himself more august not only by the rest of his dress but also especially by twelve lictors having been assumed.  [Alii] Some think that he followed number from the number of the birds which had foretold his sovereignty in the augury; it hardly discontents me to be of the opinion of those whom it pleases that both attendants of this type (adv. acc) and also the number itself was lead from their neighbors the Etruscan, whence the curule chair, whence the toga praetexta was taken; and the Etruscans considered/arranged (it) thus because individual peoples gave in common individual lictors from the twelve peoples with the king having been created.

Meanwhile the city was growing by the encroaching on some and other places with its walls because they were fortifying more in hope of future multitude than to this which was then of men (with regard to that which was the population then).  [Deinde] Then lest the multitude of the city be weak, for the sake of increasing the multitude, in the ancient plan of those founding cities, who used to lie that offspring were born to them from the earth, by drawing together to themselves a shadowy and humble multitude, he opens the place, which now is an enclosure for those descending between two groves, as a refuge.  At this time, from neighboring peoples the whole crowd was without distinction, (whether) he was free or slave, fled eager for new circumstances, and this was first of the strength for the begun multitude.  When already it hardly pained (him) of strength, he then prepares an advisory body for his strength: he creates 100  senators, whether because this number was enough or because there were only 100 (men) who could be named fathers: they were called fathers certainly from the honor, and their descendants were called patricians.