The portrait of the emperor, or of some member of the Imperial family, now almost always occupies the obverse of the coin. The reverse type is, as a general rule, some allegorical figure, such as Spes, Justitia, Salus, Pietas, etc., etc., or the representation of some one of the many provinces of the empire, _e.g._ Britannia, Judæa, etc., or again some military subject, _e.g._ legionary standards, or the emperor addressing his soldiers, together with a great variety of types, to mention which would occupy far more space than we have here at our disposal. The inscriptions on the Imperial coins contain in an abbreviated form the date of their issue, calculated by the number of times which the Tribunitia Potestas, or Tribunitian power, had been conferred upon the emperor. This office was renewed annually on the first day of January. The formula is TR. POT. or TR. P., followed by a numeral, as, on a coin of Trajan, TR. P. XX. COS. VI. IMP. XI. This means that the coin was struck when the emperor was in the possession of the Tribunitian power for the 20th time, of the consulship for the 6th time, and of the Imperatorship for the 11th time. Now, as Trajan had the Tribunitian power for the first time in A.D. 98, we get the date A.D. 116 for the coin in question. The other offices mentioned were not annual. * * * * * The following is a list of the Roman emperors, and other members of the Imperial families, arranged in the order in which it is usual to classify their coins, which is, as far as possible, chronological:-- Augustus B.C. 27-A.D. 14 Livia or Julia, wife of Augustus Agrippa