On Sun, 21 Oct 2018 at 12:51, Clive D.W. Feather <clive@davros.org> wrote:
> and not to be
> forgotten in other civil use was 1712 February 30
> https://en.wikipedia.org/wiki/February_30

Um, that one *is* normalized: it was a separate day between February 29th
and March 1st.

Except when we're speaking of normalization, we're typically referring to the proleptic Gregorian calendar, so that would have just been 1712 March 11, as that particular Friday was observed in Italy.

In Britain and her colonies, which still used the Julian calendar at the time but hadn't made the same omissions as Sweden in 1704 and 1708, that Friday was simply 1712 February 29, and Sweden, with its step back, could move forward alongside them on the following day, March 1.

* * *

Unrelated, but the year calendar views on timeanddate.com (note the different country settings) properly display the weirder months…

https://www.timeanddate.com/calendar/?year=1712&country=21 (Sweden has 1712 February 30 to resync with Julian calendar)
https://www.timeanddate.com/calendar/?year=1753&country=21 (Sweden adopts Gregorian calendar by skipping 1753 February 18–28, inclusive)
https://www.timeanddate.com/calendar/?year=1752&country=9 (Britain adopts Gregorian calendar by skipping 1752 September 3–13, inclusive)

…but, interestingly, it appears the month views only handle the cases where the month is shorter than usual, not longer:

https://www.timeanddate.com/calendar/custom.html?year=1712&month=3&country=21&typ=1&display=1 (properly displays Sweden's 1712 March starting on Saturday, despite the above)

--
Tim Parenti