Calibrating across the Julian Reform. 153
day before the Ides,” ante diem tertium Idus.^100 Our “fourteenth,” the day before the
Ides of March, is called, very simply, “the day before the Ides,” pridie Idus.Then
come the Ides themselves, and after they are passed we are counting down to the
next marker, the Kalends of the next month, April. What we think of as the six-
teenth day of March, the day after the Ides, is for the Romans seventeen (inclusive)
days before the next Kalends: ante diem septimum decimum Kalendas Aprilis.We
keep counting down (sixteen days before the Kalends, fifteen days before, and so
on) until we hit the Kalends of April, and once we have arrived at the Kalends of
April we start counting down until we hit the Nones of April, then the Ides, and
then we count down to the next Kalends, the Kalends of May, and so on through
the year.
The Republican calendar had four long months with 31 days — March, July,
October, May.^101 The other months were all short, with 29 days, apart from Febru-
ary, with 28. Even the mathematically challenged can see that (31 × 4) + (29 × 7)
- 28 adds up to only 355.^102 Caesar had to add ten days to get the 365 he needed.^103
He left the long months and February alone, and added these ten extra days, the
dies additi,to the seven short 29-day months, to make them up to 30 or 31, creat-
ing the month lengths we still use. The extra one or two days went at the end of
the month in each case.^104 The position of the Nones and Ides was therefore totally
unaffected, and the dating of any festivals counting down to the Nones and Ides
was likewise totally unaffected.^105 In the second half of the month, however, after
the Ides, as we have just seen, the Romans counted down to the beginning of the
next month, the Kalends, and having one or two extra days at the end of a month
is going to change this counting. When a festival (or a birthday) fell between the
Ides and the following Kalends in a month whose length had changed, Caesar
notionally had a choice, rather similar to the one facing the Ulster Loyalists or
George Washington. He could leave the festival on the same date, or he could
leave it on the same day. In other words, if the festival had fallen so many days
before the next Kalends in the old calendar, he could leave it the same number of
days before the next Kalends in the new calendar, even if the Kalends had “moved”
one or two days farther away. Leaving the festival with the same “date” in this
way, however, would mean that the “day” would change, for the festival would
now be further removed from the Ides, tugged toward the end of the now longer
month by the attraction of the now more distant Kalends, to which it was inextri-
cably tied for dating. The wish to keep the festivals where it felt as if they had
always been was too strong to allow for this possibility. What Caesar did was to