On this day in 1582, Pope Gregory XIII’s bull, known by its first words in Latin, Inter gravissimas, went into effect, instituting—in Catholic Europe, at least—what has come to be known as the Gregorian calendar. The idea was to alter the Julian, or Old Style, system of leap years and, by removing ten days from October 1582, adjust the timing of the Easter observance so that it better coincided with the spring season. As a result, on the Catholic calendar for October 1582, Thursday, October 4, was followed by Friday, October 15.
What does this have to do with Virginia? For starters, England, a Protestant country, did not immediately accept the pope’s reform, which meant that it was on a different calendar than much of Europe. To complicate things further, most of the Catholic countries, even before accepting the Gregorian reform, dated their new year from January 1. While remaining on the Julian calendar, Scotland adopted January 1 as the beginning of the new year in 1600. England, by contrast, began its year with the Feast of the Annunciation, known in England as Lady Day and celebrated on March 25. With the Act of Union (1707) joining England and Scotland, these date disparities caused a problem. The old ten-day disparity between the Old Style calendar and the seasons had grown, by this time, to eleven days (that’s because the year 1700 was a leap year under the Julian, but not the Gregorian, calendar), so that, according to the historian Duncan Steel, a given day might be reflected by as many as three different dates: “February 1, 1720, in Scotland, February 1, 1719, in England, and February 12, 1720, in most of the rest of Europe.”
To acknowledge these differences, many correspondents and publications, including some in Virginia, took to assigning two years—Old Style and New Style—to dates that occurred between January 1 and March 25 in the years after 1582. Here’s an example from a transcript of the Virginia trial of accused witch Grace Sherwood:
This practice of double-dating ceased when Great Britain adopted the Gregorian calendar in 1752. Two years earlier, Parliament had passed “An act for regulating the commencement of the year; and for correcting the calendar now in use.” Known as the Calendar (New Style) Act, it directed that the year 1751 would end on December 31 and the year 1752 would begin on January 1. Additionally, Wednesday, September 2, 1752, should be followed by Thursday, September 14, 1752.
In other words, Virginia history is technically ten days shorter than you thought!