Of Time, Calendars, and the Passage of Years
Orthodox Christians, Jews, Muslims, Chinese, and a few others probably have no problem with the general concept of the profusion of possible of dates being the same actual day as a result of the use of different calendars. Our Protestant ancestors were no different, but in our modern United States the calendar is seen as somewhat immutable.
Most of the Christian world operated on the Julian calendar for hundreds of years. Moreover, in early Roman usage New Year commenced on January 1st, but later Christian influences lead to a trend to count the start of the New Year on one of the great feasts - Nativity or Annunciation, or the like. Lady Day, or Annunciation (March 25), became the New Year's Day in Northern Europe during medieval times (in England during the 12th century, earlier on the Continent) and this practice continued in Great Britain until 1752.
Similarly, although the Gregorian Calendar was adopted by the Roman Catholic Church in 1582 and Catholic nations followed Rome within some reasonable time, Protestants didn't necessarily feel compelled to use the New Calendar and some delayed more than others. Obviously such a thing would, at first, smack of 'Popery.' The Old Julian calendar, adopted under Julius Caesar in 46 B.C., calculated the year as 365 1/4 days. This was eleven minutes, fourteen seconds too long, so that by 1582, the calendar and astronomical year were no longer synchronized, and the vernal equinox occurred on March 11. Pope Gregory XIII suppressed ten days to make the equinox fall on March 21. But England and her colonies did not adopt the Gregorian calendar [and change the method of marking the New Year] until September 2, 1752, by which time eleven days had to be deleted.
Thus there is recorded in one of my family's ancestral bibles the following remark:
"1752.--We came over to the new Style,--so that the next 2nd' of Sep'tr, became the 14th' by a Law--"
Many English citizens felt cheated of eleven days' pay by the Royal Decree, and they chanted, "Give us back our eleven days." Ancient British calendar customs were also somewhat unsettled by the revision, and even today Old New Year's and Old May Day are celebrated in some areas. The hawthorn or "may tree," long a fixture of May Day festivities, is now seldom found in bloom on May Day [New Calendar]. Apparently it tends to bloom around Old May Day, May 12. So England and her Thirteen Colonies [and her other possessions] were Old Calendar and Old Style [e.g., Lady Day=New Year's Day] until just a short time before the Revolution.
Because the nations were counting days and years in different ways, and many peoples were to be found in discourse with one another, even in the colonies, we see colonial records in the early 1700s reflecting the effect of differing calendars, such as this will entry:
On the fourth day of February, in the first year of our Sovereign King George of Great Britain, &c., and in the year of our Lord 1714/5 . . .
This is not ambiguous. If you count New Year from Lady Day [Old Style] then February 4 fell in 1714. If you marked the turn of the year from January 1, then it was 1715. Many dates from the early 1700s appear in this manner.
According to one list I've seen, January 1st came to be used again as the start of the year, starting in Venice in 1522. Dates when this change was made in some other countries are:
1556 Spain, Portugal, Roman Catholic Netherlands
1559 Prussia, Denmark, Sweden
1583 Protestant Netherlands
1752 England and colonies
Thus, a Dutch colonial Protestant in English-ruled New Netherland in the late 1600s could be reporting a date according to English custom, or could possibly record according to a different approach without any indication. This can give a historian headaches in trying to establish corroborating information about an event.
Fling in a little Gregorian/Julian confusion and you have a great time.
Finally, take the fact that modern historians may 'interpret' a date and adjust it to New Calendar New Style New Year without annotation and you've got the possibility that more than one reported date is 'correct.'
One mustn't get too wrapped up in this. It's enough to simply note that these issues exist and work with the records as they are - an oddity of history that not everyone looked at the world (for example, the passing of the New Year) in the way we do. I find that delightful.
I also find it delightful to think of New Year being the date of the Annunciation - the breaking forth of the New Creation in the incarnation of Jesus Christ, the Word made flesh. I think my ancestors had the greater wisdom in this.