There is again a fourth mode, common among the Romans, of indicating the special years by naming the Consuls, or one of them.

"O nata mecum consule Manlio," Horace says, when addressing his cask of wine.

That was, indeed, the official mode of indicating a date, and may probably be taken as showing how strong the impression in the Roman mind was of the succession of their Consuls.

In the following pages I will use generally the date B.C., which, though perhaps less simple than the A.U.C., gives to the mind of the modern reader a clearer idea of the juxtaposition of events.

The reader will surely know that Christ was born in the reign of Augustus, and crucified in that of Tiberius; but he will not perhaps know, without the trouble of some calculation, how far removed from the period of Christ was the year 648 A.U.C., in which Cicero was born.