Ab urbe condita

Nor need it occasion any surprise, that the arrangement which now exists since the completion of the thirty-five tribes, their number being doubled by the centuries of juniors and seniors, does not agree with the total as instituted by Servius Tullius.

For, after dividing the City with its districts and the hills which were inhabited into four parts, he called these divisions “tribes,” I think from the tribute they paid, for he also introduced the practice of collecting it at an equal rate according to the assessment. These tribes had nothing to do with the distribution and number of the centuries.

The work of the census was accelerated by an enactment in which Servius denounced imprisonment and even capital punishment against those who evaded assessment. On its completion he issued an order that all the citizens of Rome, knights and infantry alike, should appear in the Campus Martius, each in their centuries.