Lustrum censors in the Campus Martius, after the taking of the census was over. As this purification took place only once in five years, the word lustrum was also used to designate the time between two lustra. The first lustrum was performed in 566 BC by King Servius, after he had completed his census, and afterwards it is said to have taken place regularly every five years after the census was over. In the earliest period of the republic, the business of the census and the solemnities of the lustrum were performed by the consuls. The first censors were appointed in
Lustrum 443 BC, and from this year down to 294 BC there had, according to Livy (X.47), only been 26 pairs of censors, and only 21 lustra, or general purifications, although if all had been regular, there would have been 30 pairs of censors and 30 lustra. Sometimes the census was not held at all, or at least not by the censors. The census might take place without the lustrum, and indeed two cases of this kind are recorded, in 459 and 214 BC. In these cases, the lustrum was not performed because of some great calamities that had befallen the