Re: [office-comment] A typo/error referencing Julian proleptic calendar?

On Fri, Sep 24, 2021 at 1:50 PM Mike Kaganski <> wrote:

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None of the mentions defines a "Julian proleptic calendar".

Properly speaking, the Julian proleptic calendar would be the extension of the Julian calendar to dates before January 1, 45 B.C.E. when it came into effect. But I agree that "Gregorian proleptic calendar" must be what is meant.

Note that there is no single point for the Julian-to-Gregorian transition. Here's a table:

1582	France (most areas), Italy, Poland, Portugal, Spain (10 days)
1583	Austria, Germany (Catholic states) (10 days)
1587	Hungary (10 days)
1610	Germany (Prussia) (10 days)
1700	Germany (Protestant areas), Switzerland (Protestant areas) (10 days)
1752	United States (most areas), Canada (most areas),
United Kingdom (and colonies) (11 days)
1872/1873	Japan (12 days)
1916	Bulgaria (13 days)
1918	Estonia, Russia (13 days)
1923	Greece (13 days)
1926/1927 Turkey (13 days)

Other parts of the world underwent more complex transitions. ÂIn Sweden, the plan was to omit all leap days from 1700 to 1740 to provide a smooth transition from Julian to Gregorian, but the 1704 and 1708 leap days were not omitted, due to the pressure of war. Therefore, in 1712 an additional leap day, February 30, was added, undoing the 1700 leap day and leaving Sweden back on the Julian calendar. It eventually transitioned to the Gregorian calendar in 1753.