Did you know that October 5th – October 14th, 1582 did not exist. I mean, never. We just skipped those days. And this is why.
In October 1582 the change from the old, Julian calendar to the new, Gregorian was implemented. To do so and in order to have the calendar back into line with the seasons, Pope Gregory XIII deleted 10 days from the year 1582, so that October 4th, 1582, of the Julian calendar was immediately followed by October 15th, 1582, in the Gregorian calendar. Thus the period from October 5th to October 15th, 1852 never existed!
This change was explained in a 4 page edict named “Pragmatica” on the Ten Days Of The Year which was issued by King Philip II of Spain, decreeing the change from the Julian to the Gregorian calendar. (the article continues after the ad)
This is also the reason why the Catholic Easter does not always coincide with the Orthodox Easter as Catholic church follows the Gregorian calendar while Orthodox church follows the Julian calendar that never skipped those days.