A source-book of ancient history - The Search For Mecca

.
The assembly
of the
centuries
{comitia
centuriata)
The city
tribes.
(At the same
time he
probably divided
the
country, too,
into tribes.)
The growing
population.
Livy i. 44.
In fact the
number of
men of military
age at
this time
could hardly
have exceeded
nine or
ten thousand;
Ancient
World, 337.
344 Rome Under the Kings
knights for buying horses; and widows were taxed two
thousand asses yearly for the support of the horses.
these burdens were taken off the poor and laid on the
rich.
Then an additional honor was added; the right to vote
was not given to all alike, according to the custom established
by Romulus, and followed by succeeding kings, of
granting to every man the same right ;
All
but degrees of privilege
were made, so that no one might seem to be excluded
from the right of voting, and yet the whole power might
reside in the chief men of the state.
For the knights were
first called, and then the eighty centuries of the first class;
and if
they happened to differ, which was rarely the case,
those of the second were called, and the voting seldom
descended to the lowest class.
Next he divided the city into four parts according to the
regions and hills then inhabited, and he called these divisions
tribes, as I think from the tribute; for he introduced
also the method of levying taxes according to the value of
estates.
The taking of the census he hastened by the terror of a
law which threatened with imprisonment and death those
who did not present themselves to be rated. He then proclaimed
that all the Roman citizens, horse and foot, should
attend at the dawn of day in the Campus Martins, each in
his century. . . , Eighty thousand citizens are said to
have been rated in that survey.
Fabius Pictor, the earliest
of our historians, adds that such was the number of those
who were able to bear arms. This multitude made necessary
the enlargement of the city. Servius, accordingly,
added two hills, the Quirinal and the Viminal. . . . The
whole city he surrounded with an earthen rampart, a moat,
and a wall.