By the side of these new landowning full-burgesses stood the domiciled foreigners from the allied Latium, as participating in the public burdens, tribute and task-works (hence -municipes-); while the burgesses not domiciled, who were beyond the pale of the tribes, and had not the right to serve in war and vote, came into view only as "owing tribute" (-aerarii-).
In this way, while hitherto there had been distinguished only two classes of members of the community, burgesses and clients, there were now established those three political classes, which exercised a dominant influence over the constitutional law of Rome for many centuries.
Time and Occasion of the Reform When and how this new military organization of the Roman community came into existence, can only be conjectured.

It presupposes the existence of the four regions; in other words, the Servian wall must have been erected before the reform took place.

But the territory of the city must also have considerably exceeded its original limits, when it could furnish 8000 holders of full hides and as many who held lesser portions, or sons of such holders.

We are not acquainted with the superficial extent of the normal Roman farm; but it is not possible to estimate it as under twenty -jugera-.( 12) If we reckon as a minimum 10,000 full hides, this would imply a superficies of 190 square miles of arable land; and on this calculation, if we make a very moderate allowance for pasture, the space occupied by houses, and ground not capable of culture, the territory, at the period when this reform was carried out, must have had at least an extent of 420 square miles, probably an extent still more considerable.

If we follow tradition, we must assume a number of 84,000 burgesses who were freeholders and capable of bearing arms; for such, we are told, were the numbers ascertained by Servius at the first census.