In order to translate years of Indiction into years of the Christian era it is necessary first to add some multiple of 15 (_what_ multiple our knowledge of history must inform us) to 312. On the 1st of September of the year so obtained the Indiction cycle began; and for any other year of the same cycle we must of course add its own number minus one. Thus, when we find Cassiodorus as Praetorian Praefect writing a letter[190] informing Joannes of his appointment to the office of Cancellarius 'for the _twelfth_ Indiction,' as we know within a little what date is wanted, we first of all add 14 x 15 (= 210) to 312, and so obtain 522. The first Indiction in that cycle ran from September 1, 522, to August 31, 523. The twelfth Indiction was therefore from September 1, 533, to August 31, 534, and that is the date we require. [Footnote 190: Var. xi. 6.] On the other hand, when we find a letter written by Cassiodorus as Praetorian Praefect to the Provincials of Istria[191] as to the payment of tribute for the _first_ Indiction, we know that we must now have entered upon a new cycle. We therefore add 15 x 15 (= 225) to 312, and get 537. As it happens to be the _first_ Indiction that we require, our calculation ends here: September 1, 537, to August 31, 538, is the answer required. [Footnote 191: Var. xii. 22.] If anyone objects that such a system of chronology is cumbrous, uncertain, and utterly unscientific, I can only say that I entirely agree with him, and that the system is worthy of the perverted ingenuity which produced the Nones and Ides of the Roman Calendar. In the following tables I have not attempted to mark the years of the Indiction, on account of the confusion caused by the fact that two calendar years require the same number. But I have denoted by the abbreviation 'Ind.' the years in which each cycle of the Indictions _began_. These years are 492, 507, 522, 537, 552, and 567. _Chronological Tables._