Re: Why not 13 months? (Was La Systeme Metrique)

John DeLaughter (
16 Aug 1995 14:07:09 GMT

> writes:
>In article <>
> "Stephen Souter" writes:
>> [Snip]
>> 5) The inference that one or more months were *added* to the calendar ("so
>> that the emperors could have a month named after them like the other
>> gods")
>> Technically speaking, Julius Caesar *deleted* a month from the calendar.
>> Before 46 BC, the (ordinary) Roman year had 12 months, but every second
>> year a 13th intercalary month (of 22 or 23 days) was added every second
>> year much in the same fashion as we add leap days every fourth year.
>> What was *added* to the calendar were not months but days: 10 of them (to
>> bring the number in an ordinary year from 355 to 365). This was done not
>> by inventing any months but by distributing the new days around the
>> existing months. Plus there was to be an extra "leap day" every fourth
>> year.
>You obviously know your way around the calendar, so I'll ask you
>something that has been bugging me...
>If the Romans DIDN'T add two months to the year (as I have always
>believed to be the case) when did September, October, November and
> ^^^^ ^^^ ^^^
>December (respectively the seventh, eigth, ninth and tenth months
>of the ancient Roman calender) become the ninth, tenth, eleventh
>and twelfth months of the modern calendar?

And I quote from Cecil Adams, lord high knower of a lot of stuff:

"(Some historians) say that February has always had 28 days, going back
to the eight century B.C., when a Roman king by the name of Numa Pompilius
established the basic Roman calendar. Before Numa was on the job the
calendar covered only 10 months, March through December. December, as you
may know, roughly translates from Latin as `tenth'. July was originally
called Quintilis, `fifth', Sextilis was sixth, September was seventh,
and so on.
Numa, however, was a real go-getter-type guy, and when he got to be in charge
of things, he decided it was going to look pretty stupid if the Romans
gave the world a calendar that somehow overlooked one-sixth of the year.
So he decided the year would have 355 days - still a bit off the mark,
admittedly, but definitely a step in the right direction. Three hundred
fifty-five days was the approximate length of 12 lunar cycles, with lots of
leap days thrown in to keep the calendar lined up with the seasons. Numa
also added two new months, January and February, to the end of the year."

_More of the Straight Dope_, p. 161, 1988

(Cecil goes on to describe Caesar's later calendar reform of 365 days)

John DeLaughter
>By the way, great post - lots of good stuff.
>Fred "Who Nones his Ides from his Kalends..." Read
>Fred Read
>How many people do *you* know with a C function named after them ?