Was 1 B.C. a leap year?
Thomas Duda
At first I thought that I knew the answer, but sources seem to disagree on
this point.
Should 1 B.C. (or 1 A.D.) be regarded as a leap year? The basic rule that
the year must be divisible by four would seem to say "no", however that
leaves a gap between 4 B.C. and 4 A.D.
What I would really appreciate most is a citation of the appropriate
reference.
Thanks.
Tom
Benjamin P. Carter
>
>Should 1 B.C. (or 1 A.D.) be regarded as a leap year? The basic rule that
>the year must be divisible by four would seem to say "no", however that
>leaves a gap between 4 B.C. and 4 A.D.
>
A related question: wasn't March 1 the beginning of the Roman year,
and if so, what do we mean by saying that 4 B.C. (B.C.E.) or A.D. 4 (C.E.)
was (or was not) a leap year? Do we mean that a particular year starting
on 1 January and ending on 31 December contained a 29 February? Or do
we mean that the Roman year most closely approximating it contained a
29 February? Or do we mean something entirely different?
How do professional historians generally deal with questions such
as these? Is there a standard reference?
--
Ben Carter internet address: b...@netcom.com
hbd...@delphi.com
>Should 1 B.C. (or 1 A.D.) be regarded as a leap year? The basic rule that
>the year must be divisible by four would seem to say "no", however that
>leaves a gap between 4 B.C. and 4 A.D.
invention. To be concerned with the "Leap status of a year before they were
observed is irrelevant. The calender which we use for that period is based,
mostly, on the calende
rs and evidence left to us by them. Whether or not those calenders were
strictly accurate in an astrological sense doesn't matter it is what they used
and it is what we have to use.
Blair
Benjamin P. Carter
>
> ... "Leap" years are a relatively recent
>invention. To be concerned with the "Leap status of a year before they were
The Julian calendar began on 1 January 45 BC (according to George
Sarton, _A History of Science_, vol. 2, p. 322). The term "leap year"
is English and relatively recent, but it accurately describes a feature
of the calendar promulgated by Julius Caesar. There is no anachronism
in this description. Relative to the dates previously mentioned in
this thread (4 BC, AD 4), leap years are not a recent invention.
James Harvey
According to an article recently posted in sci.classics (about the date of
Saturnalia, see article i.d. <3e9jj0$d...@sashimi.wwa.com>), the leap year
rule for the Julian calendar was misinterpreted to mean every third year
instead of every fourth during the first 34 years it was in use, resulting
in 12 leap years during that period instead of 9. Augustus corrected the
error by eliminating leap years between 8 BC and 8 AD.
--
James Harvey har...@iupui.edu IUPUI IT Networks and Systems
Disclaimer: These are my own opinions. I do not speak for Indiana University.
Thomas Hamilton
been a leap year. Remember only 4 years separated 1 B.C. from 4 A.D.
We have the Venerable Bede's poor grasp of negative integers to thank
for that anomaly.
In actual fact 1 B.C. was not recorded as a leap year by the Romans at the
time. This was a result of the Romans having fouled up the perfectly good
calender Sosigenes had designed for Julius Caesar. They had observed too
many leap years in the years between 45 B.C and 8 B.C. Therefore when
1 B.C. rolled around, they deliberately did not insert the Feb 29 called
for by the normal Julian algorithm.
This and many other calender questions are discussed in the Explanatory
Supplement to the Astronomical Almanac. The AA is the standard almanac
published jointly by the US and British Navies.
tom
Benjamin P. Carter
>While the question may seem silly because leap years have only been
>invented in the last quarter millenium, if they had existed then the gap
>between the 4 BC and $ AD probably would not have been because the extra
>rule to leap years is that every second century skips a leap year because
>a year is not exactly 365 1/4 days long. So, the year 2000 will not be a
>leap year.
Ha ha. Excellent troll. I see three howlers and one clause that can't
be parsed. Did I miss anything?
Sean Vanderfluit
: Thomas Duda <tom_...@delphi.com> writes:
:
: >Should 1 B.C. (or 1 A.D.) be regarded as a leap year? The basic rule that
: >the year must be divisible by four would seem to say "no", however that
: >leaves a gap between 4 B.C. and 4 A.D.
Krieger S.M.
>: >Should 1 B.C. (or 1 A.D.) be regarded as a leap year? The basic rule that
>: >the year must be divisible by four would seem to say "no", however that
>: >leaves a gap between 4 B.C. and 4 A.D.
>:
>While the question may seem silly because leap years have only been
>invented in the last quarter millenium, if they had existed then the gap
>between the 4 BC and 4 AD probably would not have been because the extra
>rule to leap years is that every second century skips a leap year because
>a year is not exactly 365 1/4 days long. So, the year 2000 will not be a
>leap year.
2000 WILL be a leap year, 1900 wasn't and 2100, 2200, and 2300 won't be.
Also, remember that the correction to a leap year every 4 years wasn't
first implemented until 1582 (I think), so there wouldn't have been
missed leap century years in the 4 BCE to 4 CE time frame.
Now, let's get a little more complicated. Remember that it wasn't until
the 300's that the current year numbers were adopted (I think I read
that the first Christmas was observed on December 25, 325). So, assuming
the year called 325 was a year after a leap year (guaranteeing that the
leap years would fall in years evenly divisible by 4), this should mean
that the years 1, 5, 9, 13, 17, 21, 25, 33, 37, 41, and 45 BCE were
leap years.
--
Stan Krieger All opinions, advice, or suggestions, even
Novell - Summit if related to my employment or company's
Summit, NJ products, are my own.
s...@summit.novell.com
James Harvey
[snip]
>
> Now, let's get a little more complicated. Remember that it wasn't until
> the 300's that the current year numbers were adopted (I think I read
> that the first Christmas was observed on December 25, 325). So, assuming
> the year called 325 was a year after a leap year (guaranteeing that the
> leap years would fall in years evenly divisible by 4), this should mean
> that the years 1, 5, 9, 13, 17, 21, 25, 33, 37, 41, and 45 BCE were
> leap years.
The original rule for the Julian calendar was specified as every fourth
year, which was misinterpreted by the Pontifices as meaning every third
year for the first 36 years after 45 BCE. Augustus corrected the error
by omitting intercalary days between 8 BCE and 8 CE. This was mentioned
in a recent article in sci.classics in the Saturnalia thread, and it is
also mentioned in the article on the Julian Calendar in Britannica Online.
So, to answer the original question, no, neither 1 BCE nor 1 CE were leap
years.
ryanse...@gmail.com
This also makes sense if we think about it. In the Gregorian calendar, a year is a leap year if it is divisible by 4, unless it is divisible by 100 and not by 400 (the math only works for A.D. years, we'll address B.C. farther down).
Making 1 B.C. a leap year would continue the pattern as we work backwards, into the B.C. time period.
The time difference between A.D. 8 and A.D. 4 (both leap years) is 4 years. Likewise, the difference between A.D. 4 and B.C. 1 would also be 4 years (there is no year zero with the Gregorian calendar).
Similarly, the time difference between A.D. 200 and A.D. 100 (both are not leap years, because 200 and 100 are both divisible by 100, but not by 400) is 100 years. Likewise, the difference between A.D. 100 and 1 B.C. would also be 100 years.
However, the difference between A.D. 400 and 1 B.C. (400 years) is the same as the difference between A.D. 800 and A.D. 400 (also 400 years). So, to continue the pattern of every 400th year being a leap year, 1 B.C. should be a leap year according to the Gregorian calendar.
It is important to point out that if you are trying to apply the leap year calculation to B.C. dates, you should subtract 1 from the year. So if you are trying to figure out whether the year 8 B.C. is a leap year, you would calculate using the number 7. 7 is not divisible by 4, so 8 B.C. would not be a leap year. The reason we subtract 1 from the date is because there is no year zero, so we have to shift the B.C. dates over by one number (1 B.C. becomes 0, 2 B.C. becomes -1, 3 B.C. becomes -2, etc.).
If you want one more reference (and example), Sir Robert Anderson, in his book "The Coming Prince", was trying to calculate the number of days from March 14th, 445 B.C to April 6th, A.D. 32 (see https://books.google.com/books?id=zbzRDwAAQBAJ&pg=PT103&lpg=PT103&dq=%22Add+for+leap+years+116+days+Equals+a+total+of+173,880+days%22&source=bl&ots=0b493kRLUv&sig=ACfU3U3cA02EgMWtb1ajDzV_ct5td6GJtA&hl=en&sa=X&ved=2ahUKEwi-0qnZzrLoAhWYKs0KHTJoA1sQ6AEwAXoECAYQAQ#v=onepage&q=%22Add%20for%20leap%20years%20116%20days%20Equals%20a%20total%20of%20173%2C880%20days%22&f=false )
Although he doesn't seem to directly mention 1 B.C. as a leap year, he appears to include it as a leap year in his calculations. That is, he says there are 116 leap years from 445 B.C. to A.D. 32 (476 years). If you do a quick check for leap years using only the Julian calendar, there would be 119 leap years (476÷4=119). However, with the Gregorian calendar, in a period of 400 years, 3 of those leap years become common years.
So in the case of Anderson's calculation, the years 301 B.C. (-300), 201 B.C. (-200), and 101 B.C. (-100) would not be considered leap years, but 1 B.C. (0) would be considered a leap year in order to continue the pattern set forth in the Gregorian calendar.