Pretty significant day. The Papal States, France, Poland and Spain adopted the revolutionary Gregorian calendar on Thursday, October 4, 1582 — the NEXT DAY then having become Friday, October 15, 1582. Pretty incredible. 10-days were just expunged. Gone. Poof. If your birthday fell between October 5 to October 14, you were out of luck in 1582. Your birthday vanished.
In reality the adoption of the calendar did not cause much of a stir. Much of the European population, at the time, were not that concerned about daily calendars. They went by the seasons and each day as it unfolded.
But, this was a BIG day. It demarcated history’s very timeline!