Behind the Line – Two Calendars

“As if in dark celebration of the turn of the century, a fever descended upon the inhabitants of Conway House on Lady Day, the first day of the New Year.”

The Day the Pirates Went Mad, Chapter 2: Conway House, pg 7.
#TDTPiratesWentMad - Two Calendars - Inter Gravissimas
Public Domain via Wikipedia

In historical fiction, we try to understand and capture how the world was while telling our own tale. However, the world has always been changing and it is not always easy to know when a change, definitively, occurred. This is especially challenging when the calendars we use to track the passage of time are also changing.

Different calendars have been (and some still are) used around the world. The most widely used, the Gregorian calendar, is the modern day incarnation of many changes and reformations over the centuries as needs evolved and astronomy improved. Most recently, historically speaking, was the change from the Julian to the Gregorian calendar. But, as with many such things, it wasn’t an overnight change. In fact, it took 170 years for England to make the switch, and Greece took until 1923! This can cause a bit of difficulty when doing research for your historical novel.

The Two Calendars

The Julian calendar: The Roman calendar was getting out of hand. So Julius Caesar (after whom the month of July was later named) ordered a reformation of the Roman calendar in 46 BC to bring the calendar into close agreement with the solar year. This included abolishing the practice of having an intercalary month sometimes inserted between February and March, changing the lengths of the months, and providing a system for leap years. A massive one-time adjustment of three months worth of days was also added to 46 BC to allow for this re-alignment. Then, for the next ~1600 years, the Julian calendar was predominant in the Roman Empire and much of the Western world.

The Gregorian calendar: The Julian calendar overestimated Earth’s solar year by a tiny fraction (365.25 days vs. 365.24217 days), which began to add up into full days as the centuries passed. By 1582, the Julian calendar had caused enough drift that the date for the spring equinox was well before its actual occurrence. To have the correct timing for this equinox was required to calculate the date of Easter. So in 1582, an adjusted calendar was decreed in a papal bull issued by Pope Gregory XIII. The new calendar used a different scheme for spacing out leap years to make the average calendar year 365.2425 days long – more closely approximating the actual solar year and stopping the drift of the calendar with respect to the equinoxes. The other change was to account for drift that had already occurred – the date needed to be advanced by 10 days when the new calendar was introduced.

Dual Dates & the New Year

Long before England (and the wider British Empire) adopted the Gregorian calendar, the date of the New Year caused certain difficulties as well. Prior to 1752, Great Britain and its colonies started the legal year on Lady Day, March 25th (except in Scotland since 1600), but commonly held the New Year to have started on January 1st. So a day between January 1st and March 25th might be noted in paperwork, letters, journals, etc. to be belonging to two years, eg: February 10, 1701/2.

Then, while the Gregorian calendar was being as implemented across Europe, the dual dates might be noted as February 10/21, 1701/2 (there being a difference of 11 days at this point). Or it might be more clearly spelled out, like in this special example from the London Gazette about the calendar change, where the issue covers five days.

“From Tuesday September 1, O. S. to Saturday September 16, N. S. 1752.”

The London Gazette, 1752

Where in the above quote, “O. S.” stands for “Old Style” and “N. S.” stands for “New Style” in regards to the Julian and Gregorian calendars respectively.

Research Implications

While researching events during the calendar transition period for The Day the Pirates Went Mad, sometimes dates might be adjusted to Gregorian, sometimes they were Julian, and sometimes they were clearly marked as Old Style and/or New Style. I just had to be on guard for these possibilities when building my timelines. For example:

  • the fever at the orphanage
  • the death of King William III and subsequent coronation of Queen Anne
  • the dates in the logbook written by Captain Stevens of the Swift
  • the date England officially entered the War of the Spanish Succession

Where it was possible to confirm, dates could be directly referenced in the story. Where it was not, events could be shifted around to avoid any potential issues.

And that’s what’s behind the line in the quote above. 🙂