Intercalation

Sed ut hos annos omittam caligine iam profundae vetustatis obductos, in his quoque, qui sunt recentioris memoriae et ad cursum lunae vel solis instituti, quanta sit varietas facile est cognoscere, si quis vel in unius Italiae gentibus, ne dicam peregrinis, velit inquirere. nam ut alium Ferentini alium Lavinii itemque Albani vel Romani habuerunt annum, ita et aliae gentes. omnibus tamen fuit propositum suos civiles annos varie intercalandis mensibus ad unum illum verum naturalemque corrigere.

But let me pass over these years [of the earliest peoples], already lost in the darkness of the distant past. Even among the years of more recent memory, set by the course of the moon or the sun, it is easy to see how much variety there is. One only has to look at the peoples of Italy alone, to say nothing of foreign ones. The people of Ferentinum had one year, those of Lavinium another, the Albans and the Romans others again, and so did other peoples. But all of them aimed to correct their civil years to match the one true, natural year, by inserting extra months in different ways.

denique cum intercalarium mensem viginti duum vel viginti trium dierum alternis annis addi placuisset, ut civilis annus ad naturalem exaequaretur, in mense potissimum Februario inter terminalia et regifugium intercalatum est, idque diu factum prius quam sentiretur annos civiles aliquanto naturalibus esse maiores, quod delictum ut corrigeretur, pontificibus datum negotium eorumque arbitrio intercalandi ratio permissa.

Next it was decided to add an extra month of 22 or 23 days every other year, so that the civil year would equal the natural one. It was usually inserted in February, between the Terminalia and the Regifugium. This went on for a long time before anyone noticed that the civil years were somewhat longer than the natural ones. To correct this fault, the task was given to the pontiffs, and the method of inserting months was left to their judgment.

adeo aberratum est ut G. Caesar pontifex maximus suo III et M. Aemilii Lepidi consulatu, quo retro delictum corrigeret, duos menses intercalarios dierum LXVII in mensem Novembrem et Decembrem interponeret, cum iam mense Februario dies III et XX intercalasset, faceretque eum annum dierum CCCCXLV, simul providens in futurum ne iterum erraretur: nam intercalario mense sublato annum civilem ad solis cursum formavit.

Things went so far wrong that Gaius Caesar, as chief pontiff, set out to correct the past error. In the year when he was consul for the third time, with Marcus Aemilius Lepidus, he put two extra months, of 67 days in all, between November and December. He had already inserted 23 days in February, and so he made that year 445 days long. At the same time he made sure the error would not happen again. He did away with the extra month and shaped the civil year to the course of the sun.

cum ergo Romani ex hac distributione Pompilii ad lunae cursum sicut Graeci annum proprium computarent, necessario et intercalarem mensem instituerunt more Graecorum.

Under this arrangement of Pompilius the Romans counted their year by the course of the moon, as the Greeks did. So they also had to set up an intercalary month, after the Greek custom.

omni autem intercalationi mensis Februarius deputatus est, quoniam is ultimus anni erat, quod etiam ipsum de Graecorum imitatione faciebant. nam et illi ultimo anni sui mensi superfluos interserebant dies, ut refert Glaucippus, qui de sacris Atheniensium scripsit. uerum una re a Graecis differebant.

Every intercalation was assigned to February, since it was the last month of the year. This too they did in imitation of the Greeks, who also put their extra days into the last month of their year, as Glaucippus reports in his book on the rites of the Athenians. But the Romans differed from the Greeks in one thing.

Verum fuit tempus, cum propter superstitionem intercalatio omnis omissa est, non numquam uero per gratiam sacerdotum, qui publicanis proferri uel imminui consulto anni dies uolebant, modo auctio modo retractio dierum proueniebat, et sub specie obseruationis emergebat maior confusionis occasio.

There was a time, though, when superstition led them to leave out the intercalation altogether. At other times the priests, as a favor to the tax contractors, deliberately lengthened or shortened the year. Days were added at one time and taken away at another, and under a show of strict observance the confusion only grew.