Bones, Rocks and Stars
The Science of When Things Happened
By Chris Turney
Macmillan Copyright © 2006 Chris Turney
All rights reserved.
THE EVER-CHANGING CALENDAR
O aching time! O moments big as years
John Keats (1795–1821)
The calendar we take for granted today has many a tale to tell. Spanning nearly 4000 years, it's had its fair share of ups and downs. Before the third millennium BC, the calendar hadn't really got going in a form we'd recognize today. The odd bone has been found, marked with enigmatic notches but no one can seem to agree whether these record the earliest means of timekeeping. Even if these marks did actually record days or nights, there doesn't seem to have been a widely accepted calendar that prehistoric people worked to. Most individuals probably just had to make do with a list of days numbered into the future from a fixed point of time. Anyone who didn't have a bone to hand would have had to make do with fingers and toes. That's no way to make any long-term plans. Fundamentally, our ancestors needed a calendar. But how to make one?
Two of the most important concepts needed for a calendar system are 'month' and 'year'. Now most people would agree that defining a 'month' as a full cycle of the different phases of the Moon sounds reasonable. The Babylonians, who inhabited what is roughly modern-day Iraq, certainly felt so and started using this system as far back as 3500 years ago. Each day began at evening, with the month starting on the first sighting of the crescent of a new Moon. This is a dependably regular 29.5 days and extremely tempting to use as the basis of a calendar. The first Babylonians did just that. Their calendar was made up of 12-lunar months of 29 and 30 days, and started during the northern hemisphere spring when the day and night are the same length: the vernal or spring equinox.
Using a variation of the Babylonian scheme, the Romans developed a 10-month calendar. This was supposedly started by one of their founding fathers, the warrior king Romulus, in 753 BC, the year of Rome's formation. In the Romans' scheme, the year began on March 1, with the months being named in a haphazard way. Even now we live with many of these original names, although some might seem a little odd for today's calendar – Aprilis, for raising pigs, Maius, for a provincial Italian goddess, Iunius, for the queen of the gods and, imaginatively: September, October, November and December for the seventh, eighth, ninth and tenth months of the year.
The problem both these civilizations realized, is that a calendar based purely on the changing phases of the Moon is not that accurate for tracking the seasons. To get over this, the Babylonians added the odd month now and again to keep things on course. The Romans had to be more drastic. They modified their 10-month calendar to include the months of Ianuarius and Februarius to try to make up the distance. But for the Romans, there still remained an alarming, ever-increasing difference between the seasons and the time of the year. The penny finally dropped that a 'pure' lunar calendar was no way to define a year.
An alternative way of defining a year is the length of time it takes the Earth to rotate around the Sun. One way to do this is to measure the time between two successive vernal equinoxes; the so-called tropical or solar year. Today, the tropical year is 365 days, 5 hours and approximately 49 minutes. This 'year' is a whole 11 days longer than one of 12-lunar months. After just 16 years, summer in a lunar-based calendar would be in the middle of the winter season. This was absolutely hopeless for long-term planning, especially in agriculture, which was a mainstay of the Roman economy.
In response, a group of Roman priests called the pontifices were tasked with keeping the calendar on track by adding days through the year. Although this sounds a great way of preventing any drift and keeping the system on track, there was another problem: the pontifices were notoriously corrupt. For years, no one beside the pontifices really understood the way the extra days were added and as result the system was ripe for abuse. Rather than including days in a predictable manner, the pontifices would frequently add or delay the introduction of days, and in some cases months, whenever it suited them; either for personal financial gain or to see their preferred candidates hold offices of power for as long as possible. Chaos frequently ensued.
By 190 BC, the Roman calendar was a full 117 days off, but somehow between 140 and 70 BC, the pontifices had managed to get the calendar back on track with the seasons. They soon lapsed again and by 46 BC, a 90-day difference had become the norm. Julius Caesar consulted astronomers about what to do. In 46 BC, the final 'Year of Confusion', Caesar added two temporary months, extended the length of all the months to make a total of 365 days and renamed the first month of the year as Martius, after the god of war. The jubilant public believed their lives had been extended by 90 days. More importantly, 45 BC was back in phase with the seasons.
Even with 365 days, this scheme did not fully capture a true year. Caesar argued that by adding an extra day every four years, the 'leap' year, he could correct for the missing six hours or so. This would keep the calendar on track with the seasons, or so Caesar believed. Shortly before Caesar's assassination in 44 BC, the Roman Senate was so impressed with the effectiveness of this long-overdue reform, it voted to rename one of the months Iulius, better known today as July, in his honour. Predictably, old habits die hard and after Caesar's assassination, there was a misunderstanding: the pontifices added the leap year once every three years. Only during Augustus Caesar's reign was this mistake corrected, by stopping the addition of leap years until the calendar was back on track after AD 8. For this and other political honours, the sixth month of the year was renamed Augustus, completing the full suite of month titles we use today.
This is not to say that there weren't other attempts to rename the months of the year. The Emperor Tiberius, in a moment of unusual discretion, overruled attempts by the Senate to rename September and October after himself and his mother. Commodus took quite a different tack and tried to have all the months altered to the other names of himself. Famously, December was changed to Amazonius after his obsession for the warriors of this name. Nero was a little more circumspect and only had Aprilis renamed Neronius to celebrate a failed assassination attempt. More recently, in the eighteenth century, the French revolutionaries had all the Roman names replaced by descriptions of the typical climate for each month. Thermidor, for instance, was the Hot Month. But this was totally hopeless for a country aspiring to an empire spanning different parts of the world. Unfortunately for those concerned, no one else felt quite the same about their stabs at calendrical immortality and any name changes after Augustus were soon dropped.
* * *
The Julian scheme is a reasonable first stab at a decent calendar, but at 365 days and 6 hours long, it does not track time as faithfully as might first appear. It gains 11 minutes on a real year. Over the course of one lifetime, an individual wouldn't notice the difference; it would take around 130 years before one extra day was gained. The problem was that over the long term, it did get noticed. By the mid-sixteenth century, the calendar had gained a total of 12 days against real time.
This shift had serious implications for the Christian calendar; most critically, which day to celebrate the most important religious event of the year – Easter? As Christianity spread across Europe and beyond, increasingly different biblical interpretations were being made as to when Easter should be celebrated. The Gospels were ambiguous as to when precisely the resurrection of Jesus Christ took place. Throw in the fact that the Gospels were recording the events using the Jewish, lunar-based calendar and confusion reigned. When should the celebration be made using the Julian calendar?
In AD 325, a meeting of Christian leaders at Nicea, in present-day Turkey, tried to reconcile these uncertainties. Finally a compromise was made. These early Church leaders decided to combine the phases of the Moon with the solar calendar devised by Julius Caesar. It was agreed that Easter would be the first Sunday after the first full Moon following the vernal equinox. The result has confused people ever since: the date of Easter varies each year and ranges from 'early' to 'late'. But the deed was done. Easter was forever linked to the timing of the vernal equinox.
In the mid-sixteenth century, a meeting of religious leaders at Trent in Switzerland finally agreed that the offset between the calendar and real time needed to be addressed urgently. They authorized Pope Gregory XIII to investigate. Gregory followed Caesar's lead and took advice from astronomers. In 1582, he proposed removing 10 days from October of that year. This set the vernal equinox to March 21, the recalculated date for this event when the agreement was made at Nicea, over a millennium earlier.
To make sure the calendar was self-correcting and the whole palaver never had to be repeated, the leap years were continued as before except at the end of each century: only one in four have an extra day added. As a result, 1600 was a leap year, but 1700, 1800 and 1900 lost the February 29 they would have had under the Julian calendar. The revised scheme only gains half a minute over a year and takes 2880 years before one day has to be added against real time. At last, the calendar truly matched real time. The Gregorian calendar had arrived.
Unfortunately for Gregory XIII, it was not a great time to establish a new calendar across Europe. The Reformation had started in 1517 when Martin Luther had pinned a list of complaints against the Church on the German cathedral of Wittenberg. Change had swept across Europe, which was now made up of a patchwork of Catholic and Protestant nations. The result was that when the changes were announced, most Catholic countries welcomed the Gregorian calendar and introduced it soon afterwards; Protestant countries were more wary. In Great Britain, Elizabeth I was enthusiastic but was stalled by Protestant clergy. Where the changes were made in Catholic Europe, it was often with comical results. In Belgium, the correction was introduced on 21 December in 1582, resulting in the next day being 1 January 1583 and the entire population missing Christmas.
One of the fallouts of the change was that travelling only short distances between different European Christian states created significant problems. You could leave a Catholic country one day and arrive in a Protestant state before you had left. The offset between the calendars was magnified when going to Great Britain or its fledgling empire because of the difference in the date for the start of the year. Using a Gregorian calendar, the year began on January 1, but in Great Britain the traditional Julian year started on March 25. A traveller going from Continental Europe to Great Britain between January 1 and March 24 would, on paper, have gone back in time by a year.
Britain and her colonies only adopted the new calendar in September 1752; but by this time 11 rather than 10 days had to be removed from the calendar due to a century passing since its acceptance in Continental Europe. Many people were enraged at the loss of these 11 days. William Hogarth produced a print called An Election Entertainment, which has a banner demanding: 'Give us back our eleven days'. 'Time riots' were common, one of which in Bristol resulted in the deaths of several people.
This issue also had serious financial implications for those collecting tax and rents. During the first full year of the Gregorian system in 1753, bankers refused to pay the appropriate taxes until 11 days after the traditional date of March 25. The result: the British tax year started on 6 April and continues to do so; a relic of the great changes that took place over 250 years ago.
Other Christian countries and denominations remained surprisingly loyal to the Julian calendar. Although Sweden changed in 1753, just one year after Great Britain, many Eastern European countries did not change until the twentieth century: Greece only made the shift in 1924. The Eastern Orthodox Church continues with a variation of the Julian calendar, while nationally, Ethiopia continues to do the same, with no immediate plans to change.
Non-Christian countries and faiths felt even less urgency to adopt the Gregorian system. The Islamic religious calendar continues to be based on a lunar scheme and changes through real time: the New Year drifts from winter to summer over the course of 17 years. At a national level, Turkey only took on board the Gregorian dating system in 1926. China was later still, only accepting the scheme in 1949.
While it's all good fun to see how people have responded to the developments in the calendar over the years, we clearly haven't moved on that far. We're not immune to misunderstanding how it works. How many of us decided to celebrate the start of the new millennium on 2000 when there had never been a year zero? If nothing else, at least history does teach us we need to get the time right if we want to have a party.
A HERO IN A DARK AGE
Lives of great men all remind us We can make our lives sublime, And, departing, leave behind us Footprints on the sands of time
Henry Wadsworth Longfellow (1807–1882)
For a brief moment, dream of a world with a sword in a stone, knights in shining armour, a Round Table and a beautiful queen. Sound familiar? The popularity of the myths of King Arthur is curiously tenacious. Pre-Raphaelite painters were particularly obsessed, while Star Wars supposedly puts the story into the future. So strong is the image of Arthur it is easy to presume he was a medieval British bloke, albeit a chivalrous one. The problem is that the British leaders of the medieval period are all accounted for. There is literally no time left for Arthur to have existed. But what if we're wrong?
The key to whether there ever was a King Arthur lies in documents: books, letters and poems. But these are notoriously difficult to interpret. Although it's comforting to think of history as unbiased, it's not. Even today, we can read about world events and know we're only getting one particular point of view. Once we try going back in the past, this bias becomes even more difficult to detect. We no longer have a broad overview of different opinions, just a snapshot of views peppered through time.
Picture a humourless historian of AD 3000 discovering an ancient documentary called The Holy Grail, recorded by what appears to be an esteemed group of academics called Monty Python. Although the film was not made in the Arthurian period, our future historian might assume that there is some historical basis for the tale. It's not a huge leap of faith to then take the date of AD 932 from the beginning of the film as the date for King Arthur's existence. At the beginning of the documentary, Arthur introduces himself as King of the Britons and defeater of the Saxons. Using other sources, this would seem intriguing to our historian because at this time the German and Danish tribes that made up the Saxon race had conquered much of Britain. A Saxon king called Ethel-stan was actually on the throne in England in AD 932. The point is: given enough time, common knowledge that seems obvious at the time can be lost and totally misinterpreted by future generations.
Some of the first popular stories of Arthur date from early medieval times and were written by an eclectic group of individuals. One of these was Geoffrey of Monmouth, a Norman–Breton cleric who rose to become a bishop towards the end of his life, whose The History of the Kings of Britain was 'published' in Latin in 1138. In stark contrast, Sir Thomas Malory, who wrote Morte d'Arthur (Death of Arthur) in 1470, was accused of murder, rape, extortion and robbery on more than one occasion. He only seems to have got around to writing Morte d'Arthur during one of his frequent sojourns in prison. Between them, we have the basis for most of the myths we enjoy today (Continues...)
Excerpted from Bones, Rocks and Stars by Chris Turney. Copyright © 2006 Chris Turney. Excerpted by permission of Macmillan.
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