score:4
You do realize, I hope, that Gregorian dates don't exist before 1582. The date difference with the Julian calendar was 11 days in the 1700's; and 11 centuries earlier, skipping the years divisible by 400 (namely 1600, 1200, and 800), the date difference was 11 - (11-3) = 3 days as you have noted.
Also this comment, which I made earlier below:
Both dates are true. The calendars (Julian and Gregorian) count days differently, which is why the dates are in variance. If you think that is confusing: imagine how life was in English speaking countries between 1582, when the Catholic countries largely adopted the Gregorian calendar, and 4 Sept 1752 when the English speaking countries did. Every letter had to be written with both dates, styled new and old, in order to be unambiguous.