leave the festivals on the same “day,” the same number of days after the Ides, even
though this meant changing their “date,” the notation that marked their position
relative to the following Kalends.^106
The festival of Apollo may serve as an example. The anniversary of the foun-
dation of his temple in 431 b.c.e.fell, in the Republican calendar, on what we call
23 September. Since the Republican September had 29 days, the Romans’ equiva-
lent of 23 September was “the eighth day [by inclusive counting] before the
Kalends of October,” ante diem octavum Kalendas Octobris.Caesar’s reform, how-
ever, added one more day to September to make it a 30-day month. If Apollo’s day
had stayed on the Republican date, “the eighth day before the Kalends of Octo-
ber,” then it would have moved one day away from its old spot, since there was
now one more day to go before reaching the Kalends. Caesar’s formula instead
leaves Apollo’s festival on the same “day,” the same number of days after the Ides,
but it now needs a different date: it is now no longer eight but nine days before the
Kalends of October: ante diem nonum Kalendas Octobris.
I have not selected the example of the festival of Apollo at random, because “23
September” is of course also the birthday of Augustus, and we may use this day to
return to the Roman birthday.^107 Suetonius records that the future Augustus was
born on “the ninth day before the Kalends of October” (Aug.5); since he was born
in the year 63 b.c.e., under the Republican calendar, the question immediately
arises of whether Suetonius is giving a Republican date (corresponding to 22 Sep-
tember, in a 29-day September) or a Julian one (corresponding to 23 September,
in the new 30-day September). I am sure that Suerbaum is correct to argue that
Augustus was born on the festival of Apollo, twenty-three days into the month,
and that the same thing happened to his birthday as happened to the festival:
between 63 and 46 b.c.e.his birthday and the festival were both described as “the
eighth (inclusive) day before the Kalends of October,” and from 45 b.c.e.on
birthday and festival were both described as “the ninth (inclusive) day before the
Kalends of October.”^108 The coincidence of his birth on the day of Apollo must
have mattered greatly to Augustus, who cultivated this god all his life: the last
thing he will have wanted to do in September of 45 b.c.e.was to celebrate his eigh-
teenth birthday on a day that for the first time was not the feast day of Apollo. Still,
his recalibration of the date of his birthday obviously generated a degree of con-
fusion, and some keen, or cautious, cities celebrated his birthday on both the eighth
and the ninth day before the Kalends of October just to be absolutely sure.^109
Others recalibrated their birthdays as well. Some birthdays, of course, just as
some festivals, were left unaffected by Caesar’s reform. If your birthday fell in the
- Years, Months, Days I: Eras and Anniversaries