Year in dates near the end of a year

Question

Using the traditional dates of the Roman calendar, December 31 and December 30 would be pridie Kalendas Ianuarias and ante diem tertium Kalendas Ianuarias. The day is expressed in relation to the first day of the next month. This happens for all days after Idus. For more about writing dates, see this recent question.

If I want to include the year in my date, which year is it? The one of the Kalendae Ianuariae or the one of the day itself? If I want to describe my plans for the end of this year, I seem to have two options:

On December 31, 2016 I will sleep.
Pridie Ianuarias anno 2016/2017 dormiam.

My guess would be 2016. But if I used anni instead of anno instead — which I find unusual but grammatical — then I would choose 2017.

Which year should I choose and why? Have both options been in use? Have grammarians or other scholars commented on this issue?

Answer 1

The Romans denoted the year by naming the consuls (though one can see that it might have been rather awkward when the second of two consecutive days coincided with the appointment of new incumbents), until the more convenient system of anno domini was introduced to denote successive years from the birth of Christ, a far neater arrangement which simultaneously removed all doubt about the calendar year in which any date fell.

It isn't necessary to use the Roman method of Kalends, etc. Writers in more recent centuries generally took the easy course offered by the modern system, so that New Year's Eve for this year would simply be written XXXI [mensis] Decembri MMXVI (though you may feel that some expression on the lines of pridie Novum Annum MMXVI is more elegant in your own circumstances). I suggest that where a modern form is widely approved, it's OK to use it. After all, if you are writing or speaking of modern topics for which neologisms have had to be invented, why not use this one, too?

[A footnote may be of interest here: he British parliament used to date its Acts by the regnal year of the monarch, e.g. the Duchy of Lancaster Act 1812 is recorded as '1812 CHAPTER 161 52 Geo 3', it being the 52nd year of the reign of King George III — an echo of the ancients' use of, for example, C. Pansa et A. Hirtio consulibus . . . ]