Ab urbe condita

Titus Livius (Livy)

Livy. History of Rome, Volumes 1-2. Roberts, Canon, Rev, translator. London, New York: J. M. Dent and Sons; E. P. Dutton and Co., 1912.

Even on that occasion Tarquin was deterred from making changes in the names or numbers of the centuries of knights; he merely doubled the number of men in each, so that the three centuries contained eighteen hundred men.

Those who were added to the centuries bore the same designation, only they were called the “Second” knights, and the centuries being thus doubled are now called the “Six Centuries.”