Livy Periochae 13) until 280 BC. In 131 BC, for the first time, both censors were plebeians.

The reason for having two censors was that the two consuls had previously taken the census together. If one of the censors died during his term of office, another was chosen to replace him, just as with consuls. This happened only once, in 393 BC. However, the Gauls captured Rome in that lustrum (five-year period), and the Romans thereafter regarded such replacement as "an offense