I am trying to decide if Desire Toogood's recorded birth date 26 March 1734 could be wrong. The record also states it was the 2nd day of the week, so it should have been a Monday. And it was recorded in Massachusetts, so was under English calendar conventions.
The English switch to the Gregorian Calendar lopped off 11 days in September of 1752, with 2 September being followed by 14 September. My presumption is that if 14 September was a Thursday under the Gregorian calendar, then the previous day was still what we would call a Wednesday (i.e., 4th day of the week), but written under the official Julian calendar it was 2 September. That would mean that if this calculator had kept going, the 14th of September would instead have been a Monday. So looking at a date number that would have been a Monday under the Julian calendar, if you look at the same date number on the Gregorian calendar it was a Thursday.
But now I am getting confused because when I look around at some online date calculators, I don't see them behaving like I'd expect. For instance, this one does not seem to have a break in the calendar on 25 March for year numbers before 1752, i.e., 1734. It shows 25 March 1734 as a Monday, while 24 March 1734 is a Sunday, even those these dates were separated by 364 days and should have fallen on the same day of the week. The calculator insted seems to be thinking that under the Julian calendar, 25 March 1734 occured the day after 24 March 1734.
This one shows similar behavior: it reports 25 March 1734 as a Thursday under Gregorian and Monday under Julian, but then moving to 24 March 1734, it reports these were a Wednesday and a Sunday.
I feel like I have a fundamental misunderstanding about how the calendar change was implemented. Any clarity would be very much appreciated.