Censor (hat. censere, to estimate), the title of Roman magistrates of high dignity and great influence, instituted in the year 443 B. C. The office was vested in two persons, originally elected for five years, from and by the patrician order; but later changes introduced by the dictator Mamercus, 433 B. C, and afterward, reduced the term of the office to 18 months, and made it attainable by plebeians, of whom Rutilus, who had also been the first dictator of that order, was the first elevated to this dignity (351); and in 131 even both censors were plebeians. They had all the ensigns of consular dignity except the lictors, and wore a robe of scarlet. Their office was to take the regular census and keep the rolls of all Roman citizens, to distribute them according to orders, tribes, etc, to value, register, and tax their property, to control public morals and manners, to till remarkable vacancies in the senate, to choose the princeps senatus, to manage the farming of the revenues, customs, and salt monopoly, to contract for repairs of public buildings and roads in Rome and Italy, etc.

They had the right of punishing moral and political transgressions committed by citizens of distinction with marks of ignominy, by expulsion from the senate, and even by degradation from a higher to a lower order; for which punishments the ill-treating of members of their families, extravagance, and the pursuit of mean professions, were regarded as sufficient reasons; but their decisions were subject to an appeal to the assembly of the people, and themselves to its jurisdiction. The dignity of censor was regarded as most honorable, and originally only those were eligible who had passed through all other offices. The emperors assumed it under the title of morum praefecti; Decius desired to restore it independently under a particular officer. The brother of Constantine the Great was the last censor.