Reading the article, I wandered into the difference of Old Style and New Style dates and what happened in 1752.
From [1]: By the 18th century, the English legal year – used for legal, financial and other civil purposes – had for centuries begun on 25 March, or Lady Day.[13][i] Thus, for example, 24 March 1707 was immediately followed by 25 March 1708, while the day following 31 December 1708 was 1 January 1708, with 1709 still nearly three months away.
To this day the UK tax year still begins on April 6th, for reasons [1] that have to do with the migration from Julian to Gregorian calendars almost 300 years ago. I wonder if other countries have so many of these legacy patches from ye olden times.
Though note the wiki page for Carroll's method[1] states:
1676, February 23
...
Dates before 1752 would in England be given Old Style with 25 March as the
first day of the new year. Carroll's method however assumes 1 January as
the first day of the year, thus he fails to arrive at the correct answer,
namely "Friday".
...
It is noteworthy that those who have republished Carroll's method have
failed to point out his error"
I've been amused by this for a while, although I think when I first saw it I didn't realize that there was so much country-to-country variation in what year the Gregorian calendar was legally adopted.
Maybe a better (or much worse!) behavior would be to show the switch in the current locale, so in ru_RU it happens in 1918, but in es_ES (or es_MX, es_CO, es_AR, es_PY, ...) it happens in 1582.
From [1]: By the 18th century, the English legal year – used for legal, financial and other civil purposes – had for centuries begun on 25 March, or Lady Day.[13][i] Thus, for example, 24 March 1707 was immediately followed by 25 March 1708, while the day following 31 December 1708 was 1 January 1708, with 1709 still nearly three months away.
Thank goodness that happened.
[1] https://en.m.wikipedia.org/wiki/Calendar_(New_Style)_Act_175...