FROM THE OFFICE OF THE MASTER SECRETARY
Robert fitz John wishes to promulgate the following treatise upon the subject of calendars.
The word 'calendar' comes, somewhat indirectly, from the Latin 'Kalendae', denoting the first day of a month, via 'Kalendarium', which originally meant an account book (because monthly interest was due on the first day of each month).
The calendar most of us use today is based on the one introduced by Julius Caesar in 45BC. This formalised the sequence of months with which we are familiar, with the year starting on 1st January. He intended there to be one 'leap year' every four years, but this wasn't done properly until the emperor Augustus straightened things out, with 8AD being a 'leap year', then 12AD, 16AD, and so forth.
The term for a leap year was 'bissextile', which means 'containing two sixes', because the extra day was included by repeating the day known as '6 days before the Kalends of March', which we call 24th February. In a leap year, the 25th day of February was also '6 days before the Kalends of March'. Thus, the day labelled '2 days before the Kalends of March' was 28th February in non-leap years, but 29th if the year was bissextile. (The Romans used inclusive counting, hence the last day in a month was 'two days before' the first day of the next month.) Note that the intercalated day is 24th February.
Naturally, the Romans didn't use the terms 'BC' (before Christ) or 'AD' (anno Domini). Their equivalent was 'AUC' (ab urbe condita), numbering the years from the supposed date of the founding of Rome (753BC). The scholar Dionysius Exiguus, while compiling a table of dates for Easter, introduced the use of 'Anno Domini Nostri Jesu Christi' (in the year of Our Lord Jesus Christ), starting with 532AD. Dionysius arranged for 1AD to start one week after what he believed to be Jesus' birthday. The evidence suggests, however, that he was wrong by at least five years. In Dionysius' calculations, the cycle of dates for Easter repeated every 532 years, so maybe he chose 532AD as a convenient approximation.
There was, of course, no 0AD. When Bede, in the 8th Century, introduced the idea of counting backwards from 1AD, he wasn't familiar with the concept of zero. It was natural for him to name the year before 1AD as year 1 'before Christ'. (It's disputed whether Bede introduced the 'BC' system, but the principle remains the same.)
Caesar's Roman year commenced with 1st January, but in 567AD the Council of Tours, disapproving of the unholy revelry that took place on this day, decided to move the start of the civil year to Lady Day (the Feast of the Annunciation of the Blessed Virgin Mary), which is 25th March. During the Middle Ages the year was considered to start on 1st January or 25th March, depending on context and local custom. To add to the confusion, the ecclesiastical year began on 25th December. There were other dates used, but in Europe these three dates were the ones most often employed.
By the end of the 16th Century, most European countries had converged on the use of 1st January - a move that was reinforced by the introduction of the Gregorian calendar. However, the legal year in England continued to start on 25th March until the calendar reform in 1752.
The Julian calendar sets the average number of days per year at 365.2500. This is slightly longer than the mean solar year of 365.2422 days. (This figure is gradually decreasing, as the Earth's rotation slows and the days get longer.) It is also longer than the average time between Vernal Equinoxes, 365.2424 days, which is of more interest medievally, as the date of Easter is intended to be set in relation to this equinox. At the time of the Julian reform, the equinox had occurred on 25th March. By 325AD, when the Council of Nicæa set rules for the date of Easter, it had moved to 21st March, and this was decreed to be its 'proper' date. By the 16th Century the equinox had shifted by a further ten days, occurring around 11th March, as a result of the accumulated error of 11 minutes per year.
A number of popes set up commissions to try to resolve the problem, which was compounded by a lack of knowledge of the true length of the year. It was during the pontificate of Gregory XIII that the matter was resolved, by means of his Bull, 'Inter Gravissimas', which in 1582 instituted what became known as the Gregorian Calendar.
Pope Gregory's calendar reform had two main parts. Firstly, the ten days from 5th October to 14th October 1582 (inclusive) were dropped, to bring the Vernal Equinox back to 21st March. Secondly, centennial years not divisible by 400 would no longer be bissextile.
The bull explicitly stated: "...annus MDCC, MDCCC, MDCCCC bissextiles non sint. Anno vero MM, more consueto dies bissextus intercaletur, Februario dies XXIX continente...", (the years 1700, 1800 and 1900 will not be bissextile; the year 2000, as with current custom, shall have a bissextile day intercalated, with February containing 29 days). So, anyone who got that wrong had 418 years' advance warning!
The effect of this modification was to reduce the mean calendar year to 365.2425 days, which is close to the correct interval between vernal equinoxes. (An alternative scheme involving 8 intercalated days every 33 years - giving an average of 365.2424 days per year, with less 'drift' from one year to the next - was never adopted.)
Unsurprisingly, the Catholic countries adopted the Gregorian calendar almost immediately. Most of the rest of Europe had followed suit by the end of the 17th Century. Britain and its dominions waited until 1752 before switching to the new calendar. The eleven days from 3rd to 13th September 1752 were omitted and the start of the civil year was changed to 1st January. Where necessary to avoid confusion, the year number was termed 'New Style'.
The end of the tax year originally co-incided with the beginning of the civil year, on 25th March. During the calendar reform it was moved to 5th April to keep the 1752-3 tax year the same length.
It may or may not be coincidental that the Far Isles' financial year starts on 1st April. Persons who have not paid their annual taxes within a reasonable period after this date are removed from the roll of citizenship. Nobles who fail to pay before the end of April may have their titles revoked, although the Crown is usually lenient as regards the application of this rule. (Members of the Order of the Sleeping Lion are exempted from this regulation.)
The 'civil year' in the Far Isles commences on 1st October. Before independence, years were expressed from the founding of the SCA as 'anno Societatis' (AS - in the year of the Society). In the SCA calendar, AS1 ran from 1st May 1966 to 30th April 1967. We continue to use 'AS', but our calendar relates to the founding and independence of the Far Isles: thus, our AS24 began on 1st October 2000.
Note that in the Far Isles we intercalate a day in the February preceding each year divisible by four. Thus, AS23 was a leap year. Astronomical observation indicates that the vernal equinox falls on 20th or 21st March, which is not consistent with the Julian calendar after 500AD, whereby I deduce that we are operating under the Gregorian calendar. This being the case, I advise that AS123 will not be a leap year.
In our Constitution the end date for our period is stated to be 1603. I suggest that this date is New Style, as I believe it is intended to represent the end of the Tudor / Elizabethan era. Queen Elizabeth I died on Thursday 24th March 1602 (Old Style), so the next day brought in a new year along with the new (Stuart / Jacobean) era.
A ship sets sail from Portsmouth (England) on 29 February 1700 and heads for Spain. It travels 1440 nautical miles at an average speed of 6 knots and then docks in Cadiz. On arrival the captain asks the harbourmaster what the date is, and the gentleman replies (in English)...?
©2001-2005 Trevor Barker. Originally published in Far Horizons, Vol. 12, No. 2.
Permission is given to copy this work, provided it is unaltered and this copyright notice remains attached.