It gets more complicated when different countries use different calendars. A favourite example concerns the deaths of Shakespeare and Cervantes, for which some sources give the same date, 23 April 1616, and in honour of this UNESCO chose 23 April as the International Day of the Book. However, although they may have died on the same date they certainly didn’t die on the same day, because in 1616 Spain had adopted the Gregorian calendar and England had not.

Another example is the October Revolution, which occurred in November by our reckoning. By coincidence Language Hat has a pertinent post this week, in which he tells us that “In Macedonian, Listopad means October.
In Polish and Slovenian, Listopad means November.” Although this apparently has nothing to do with the October Revolution, it must generate confusion when translating texts about it into these languages.