January 1st 1 AD ?

[Vitamines]

That is a naughty question because there isn't a unique answer.
Contrary to common belief the Gregorian and Julian calendars did not
start from the same base day. January 1st 1 AD (Gregorian) - a Monday -
was January 3rd 1 AD (Julian). Unless I had specified which calendar I
was using you could not answer the question. I am sorry if you wasted
time trying to.

 

[Tim Slattery]

That is a naughty question because there isn't a unique answer.
Contrary to common belief the Gregorian and Julian calendars did not
start from the same base day. January 1st 1 AD (Gregorian) - a Monday -
was January 3rd 1 AD (Julian). Unless I had specified which calendar I
was using you could not answer the question. I am sorry if you wasted
time trying to.

There was no Gregorian calendar until 1582. The new calendar was
introduced at that time to correct the Julian (old style) calendars
imprecision. (There were no leap years in the old style calendar. But
the earth's does not orbit the sun in a precise number of days - it's
about 364 1/4 days - so Easter was on its way out of Spring.) In
Catholic countries (Protestant countries didn't come on board for
another hundred years or so), October 4, 1582 (OS) was followed by
October 15, 1582 (NS). Lots of folks were *very* upset about losing
ten days!

Lots of information about calendars at
http://astro.nmsu.edu/~lhuber/leaphist.html

Nobody was using either calendar in what later came to be known as
AD1.

 

[Thomas Fritsch]

There was no Gregorian calendar until 1582. The new calendar was
introduced at that time to correct the Julian (old style) calendars
imprecision. (There were no leap years in the old style calendar. But
the earth's does not orbit the sun in a precise number of days - it's
about 364 1/4 days - so Easter was on its way out of Spring.)

Just to be pedantic:
The Julian calendar *did* have leap years (1 year of 4), giving an
average year of 365.25 days. The Gregorian calendar has a little fewer
leap years (97 years of 400), giving an average year of 365.2425 days.
This is almost equal to the exact astronomical year of 365.2422 days.

Anyway, this doesn't change your reasoning that Easter was on its way
out of Spring.

 

[Roedy Green]

There was no Gregorian calendar until 1582.

The world gradually adopted it. I have documented inside BigDate some
of this lore. http://mindprod.com/products1.html#COMMON11

Some parts of the world still have not. Measurement of time and
religion have been strongly linked for a long time.

Under http://mindprod.com/jgloss/leapyear.html
I discuss some of the refinements proposed on the Gregorian scheme.

Much of the flipover happened under stress of WW II, so it is not even
known when it officially happened.