>>In 1582 Pope Gregory XIII (hence the name Gregorian Calendar) ordered ten days to be dropped from October, thus restoring the vernalequinox at least to an average of the 20th of March, close to what it had been at the time of the Council of Nicea. In order to correct for the loss of one day every 130 years, the new calendar dropped three leap years every 400 years. Henceforth century years were leap years only if divisible by 400. 1600 and 2000 are leap years; 1700, 1800 and 1900 are not.
>
> SEPTEMBER 1752
>
>Su Mo Tu We Th Fr Sa
> 1 2 14 15 16
>17 18 19 20 21 22 23
>24 25 26 27 28 29 30

If the 10 days were dropped in October, why would September look like that? (That's also 11 days missing in your sample)