The interval of time supposed to have been denoted by the Roman Lustrum has been made the subject of controversy. No one however as far as we know has ever assumed it at less than four years or as more than five; so that the status quæstionis may so far be considered as fixed and agreed upon: and all that we have to do at present is to begin with inquiring whether the Roman Lustrum was more properly a period of five years or one of four.