Calendar, Creating an Accurate Year

by David Ewing Duncan

It is easier to say when the world's calendar finally arrived than when it began. On 1 October 1949 Mao Zedong declared that China would follow the Gregorian calendar. For the first time the entire world agreed what the date was.This is the first complete history of the calendar, and in it are tales of science, religion, superstition and politics of many ages from Ancient Egypt to the flowering of Indian and Islamic civilisations. Julius Caesar attempted to impose a unified calendar on his burgeoning empire, but he could not calculate exactly the length of the year. His Julian calendar gained time over the true solar year,leading to calls for reform during the middle ages, most notably by the British monk, Roger Bacon. These caused all manner of mayhem as between ten and thirteen days were removed at a stroke, pitching religion against science, Catholic against Protestant, taxman against trader, and it was a full five hundred years before Europe was in synch again.The crucible for the development of astronomy and mathematics, the calendar has always been the measure of how the world is understood and evaluated, and the object of fascination for the greatest scholars. It has existed as long as time itself, but the story of its reckoning is a tale of human will, vanity, experimentation and endeavour - and the diligence of a thirteenth-century British mankind's history of time.

Genres: History, Nonfiction, Science, Microhistory, Religion, Technology, World History

Paperback

First published July 1, 1998

About the author

David Ewing Duncan is the author of seven books including the worldwide bestseller Calendar. He is Chief Correspondent of public radio's Biotech Nation, a commentator on NPR's Morning Edition, and a contributing editor and a columnist for Conde Nast Portfolio. He has been a contributing editor to Wired, Discover and Technology Review, and has written for Harper s, The Atlantic, Fortune, and many other publications. He is a former special correspondent and producer for ABC Nightline and a correspondent for NOVA s ScienceNOW! He has won numerous awards including the Magazine Story of the Year from the American Association for the Advancement of Science. He lives in San Francisco and is the Director of the Center of Life Science Policy at UC Berkeley. "

Reviews

[Frank R · Rating 2 out of 5]

One gets the sense that the author felt the material on the actual calendar wasn't quite long enough for a book, and had to bulk the text out. Half of the book doesn't deal with the calendar at all, but rather digresses into lengthy exposition on how barbaric and benighted the middle ages were. There are also digressions into the history of our number system and into various other sorta-kinda related topics. I would have much preferred the author stuck to the topic.

Also, minor errors that were not caught in revision or editing make the credibility of the whole book suspect. One travels EAST on the Thames from London to reach Oxford? Quite a feat. The year 2000 is actually the year 1997, because Jesus was born in 4 BC? How does that math work? A work of popular scientific history should not have such obvious mistakes.

So, although there is definitely interesting material on the history of our calendar, this book suffers from serious flaws. I was disappointed.

[Michael · Rating 4 out of 5]

ერთ-ერთ ინტერნეტ მიმში, ძველ საბერძნეთში, ერთი ფილოსოფოსი ეკითხება მეორეს: - "რომელი წელია ახლა?" მეორე პასუხობს: "ქრისტესშობამდე 380 " "ქრისტე ვინღა ჯანდაბაა?" უკვირს პირველს. "წარმოდგენა არ მაქვს" პასუხობს მეორე.
სკოლაში ისტორიის სწავლა რომ დავიწყე და პირველად გავიგე რომ ძველი წელთაღრიცხვა უკუთვლით მიდიოდა, ძალიან გამიკვირდა და არაბუნებრივად ჩავთვალე. არავის აუხსნია რატომ იყო ასე. რატომ ითვლიდნენ ასე უკუღმა, ვინმემ იცოდა რომ ქრისტე დაიბადებოდა? ისტორიის მასწავლებელმა თქვა რომ ეს უბრალოდ ასეა. ახალი წელთაღრიცხვის გაჩენა ასე თუ ისე გასაგები იყო, მაგრამ ძველი? მისთვის თარიღები ძალიან მნიშვნელოვანი იყო, თუმცა არა ის თუ საიდან გაჩნდა ეს თარიღები. კალენდრისადმი და ქრონოლოგიისადმი ჩემი ინტერესიც ალბათ ამ გაურკვევლობიდან დაიბადა.
რათქმაუნდა მერე გავაცნობიერე და გავიგე რომ ეს ძველი წელთაღიცხვა მოგვიანებით განჩდა, მაგრამ მაინც საინტერესო დარჩა თემა: კონკრეტულად როგორ დაიბადა ეს ქრონოლოგია, როგორ განჩდა კალენდარი? როგორ ითვლიდნენ ძველად დროს? როდის გაჩნდა Anno Domini? რატომ არის თებერვალი 28-29 დღე, მაშინ როცა ყველა დანარჩენი 30-31, საიდან გაჩნდა თვეების ეს დასახელებები? ვიცოდი რომ ივლისი და აგვისტო, იულიუსის და ავგუსტუსის საპატივცემულოდ ერქვა, მაგრამ სხვა თვეები? ან საიდან გაჩნდა კვირის დღეები და მათი სახელები?
თუ თქვენც გაინტერესებთ ეს ყველაფერი, ეს წიგნი მოგიყვებათ საკმაოდ დეტალურ ისტორიას, თუ საიდან გაჩნდა ჩვენი კედლის კალენდარი, თუ რატომ ვითვლით დროს ისე როგორც ვითვლით, რამდენად ზუსტი იყო ან არის ეს სისტემა და რა სიძნელეები გამოიარეს ადამიანებმა ვინც ის შექმნა.

[John Hoole · Rating 4 out of 5]

Doesn't join the annals of greatest non-fiction writing, but a fine piece of work on a topic I'm obsessed with: how we fix time and what is the human significance of the year and the seasons. The centerpiece of this story is how Europe adopted the Gregorian calendar, which is now the world standard. It's a fascinating story, many centuries in the making, of how a human-contrived invention came to feel natural.

[Acquafortis · Rating 4 out of 5]

A appealing fact-jammed book about something we use everyday - the calendar.
I never thought there were so many events and people involved in its story dating back to time immemorial. Facts at times amusing, others outright dramatic.
It's fascinating the interplay between time and who dictates it. Control over time and its deployment gives boundless power to the beholder that usually one can't even ponder.
Last one on the list is the Roman Catholic Church, who's reform on the calendar is the one we're still using today.
A reform that started, not for any scientific endeavour but for the down to earth task of celebrating Easter on the appropriate day!

[Alyssa Macpherson · Rating 2 out of 5]

At first this was an interesting read, but as I read more the lustre has worn off. The author is focussing on his own narrative over historical detail and sometimes even facts.

This is especially egregious in the chapters about the early Middle Ages, wherein the fall of Rome is portrayed as hordes of bloodthirsty barbarians destroying something glorious without reason, while St. Augustine and the church hate time and science but need them to calculate Easter.

Someone got all their history from Gibbon's Rise and Fall. Very disappointing, am probably not going to continue reading.

[Josette · Rating 5 out of 5]

This is a really interesting book. It's a little hard to get through in parts, but I gave it 5 stars because it's just so darn fascinating. Did you know about the 10 days that were removed from the calendar by Pope Gregory in 1582 (but not until 1752 in the American colonies?) Read this book and you'll know!

[Jane Elliot · Rating 5 out of 5]

one of my all time favourite books

[Caitlin · Rating 3 out of 5]

A good read and as easy for a lay-person to understand as I think possible when it comes to talking about the intricacies of time. (Which means I didn't understand everything, but enough to come away with a comprehensive understanding).

My biggest beef is the obvious anti-Byzantine, anti-Eastern Europe historical bias. While giving due justice to the influence of Chinese, Indian, Egyptian, and Islamic figures, the book should be more precisely termed "Europe's Epic Struggle to Create a Year Acceptable to their Understanding of the World". A few mentions of the Mayan calendar are not nearly enough to truly explore humanity's encompassing idea of a 'year'.

There's also the old tired canard that every churchman or religious person is a power-hungry ignoramus unless they believe in science in which case they *obviously* can't be very religious. While not explicitly stated, it's clearly implied and shows a lack of attempt to understand any historical viewpoint that doesn't mesh with a modern one.

So this is a good book to read if you want a brief overview of pre-European time calculation and an in-depth view on the ultimate creation of the Gregorian calendar. But read with the knowledge of historical bias and maybe check out a different history or three in addition.

[booklady · Rating 3 out of 5]

Was combing my history shelves -- for something else -- and pulled this down. Remembered what a fascinating read it was. Tells all about how the modern calendar developed. This was a 'reading room' (AKA powder room) read which is why it took almost a year to finish, but still I did read the entire book. Never knew what a complicated thing Time and its tracking is.

[Deborah Pickstone · Rating 3 out of 5]

Interesting examination of the concept of time, how the calendar (linear time) evolved and how human-made time doesn't reconcile with time as it happened and the confusion sown along the way by various interferences and the intersection of several different calendars. And all you asked was 'what time is it?' :)

[Tracy Black · Rating 5 out of 5]

At first I was disappointed that this was a history of only the western calendar. All others got, at best, a brief mention. But this was a THOROUGH history, of not only the calendar, but of the science and politics that influenced it. This is a well-written, worthy read.

[Jennifer (wildling_manor) · Rating 2 out of 5]

The beginning with all the facts was interesting, but the book became more and more dry. I skimmed the last 70ish pages.

2.5 stars

[Bill Chaisson · Rating 2 out of 5]

Calendar started strong and then lost its way a bit. I was, for example, never fully convinced that David Ewing Duncan had a firm grasp of the geometry of the Earth's motion in space. He left certain aspects of it either vague or unmentioned. He never fully explored the periodicity of the precessional cycle or gave a value for the length of the period and how extraordinary it is that the Egyptian astronomical records were so long and continuous that they actually documented part of this 19,000-year cyclical phenomenon by observation. Nor did he go into why measuring the "tropical year" at different points in the cycle yields a very slightly different year length.

He was much stronger on history than on science, but sometimes his meandered out into historical events that seemed to have only tangential relationship to the story of the calendar. The first wave of bubonic plague in Europe in the 14th century stopped in its tracks an incipient calendar reform by the Catholic Church and yet Duncan felt it necessary to give a thumbnail history of the effects of the Black Death on the European population and their culture. It is unquestionably awesome and awful, but not very germane to the story of the calendar.

He does devote a few chapters to describing calendars and clocks that were developed by non-European cultures, especially following the fall of the western Roman Empire, when technological advances were few in Europe (to be charitable). But he tells these stories mostly for the purpose of describing how the insights of the Chinese, Indians, Persians and Arabs fed back into the the reawakened European quest to refine the calendar in the later Middle Ages.

Duncan is very clear that the most significant reason to measure the length of the year accurately was to keep track of the ecclesiastical schedule of saints' days, feasts, and especially the date of Easter. If the reader takes away any insight from this book, it is that the church suppressed science for centuries and allowed the preservation of time-reckoning to determine the date of Easter. And it did that only partially and fitfully. Anyone wishing to join Richard Dawkins and other prominent atheists in condemning organized religion for its ill effects on European culture (=progress) will find plenty of ammunition here.

Duncan's writing is always serviceable and never difficult to read, but he seemed to tire of his own project in the last quarter of the book. He gives relatively short shrift to modern projects like the "World Calendar," which is an interesting attempt to regularize the Gregorian calendar so that all months have either 30 or 31 days and those alternate regularly (one 31-day month, followed by two 30-day months). To keep the book at a mangeable length and yet keep it focused on the calendar, it would have been nice to have less about the Black Death and different models of water clock and more about the World Calendar and the Calendar of Reason.

[Thanh Nguyen-Kim · Rating 4 out of 5]

Very intesting!
Different civilization kept track of time by their way (I love those written figures of months and numbers).
Also numbers weren't the same as we had. Number 0 and decimals revolutionized the numbering of days in a year.
Lunar, solar, lunisolar calendar - I am still confuses with the concept.
Trying to capture the true value of tropical year.
Relying on position of star as signal for a new year >> a sidereal year.
Sequencing of days within a month, how many months and months a year has, frequent additional day as true-up fix. Such a messy period.
The ignorance of Latin, and exchange of knowledge from Arabics.

I love the fact that despite numerous scholars threw doubts on the precision of Julious (Caesar's calendar), the urge to reform didn't kindle till the booming of interregion trade, (mass) printing that shamed someone.

Reform issued in 1582 by the pope via papal bull (Georgian calendar) made a good catch-up but still not precise. (OMG...atomic clock of 20th century).
Proposals to reform currently used Georgian calendar are still being submitted.

The missing 10 days in 1582/1583/... (or 11 days in UK) and resulting UK's tax deadline of 5th APR (11 days after 25th MAR).

Anyway, I like also summary of calendars (the name, year invented and how many days, hr, min, s in it). Also different kind of ways a year can be defined, names of months a year in different languages. Without those littlebrief summary I would be probably even more lost. Reading this book demands full concentration (but some parts told me too much about church's side of the story which bored me sometimes)

I tried to take notes as much as I could but still had to absorb passively when the difference between one calendar to the other is in .xxxabc decimal which is translated into zz seconds... Trust his calculation.

[Dennis R · Rating 4 out of 5]

Wow! Who knew that the creation of something we daily take for granted and use almost obsessively every day required this much work and took this much time? I was initially a bit leery of the book as the computation of time and the calendar is math heavy and often books about math can be boring and difficult to read.
There are flashes of that here as well as assumptions of knowledge which may prove to be tuntrue, but overall, Duncan avoids getting lost in the weeds of math and tells a good history of the development of ideas and concepts about time. He also points out the extreme confusion existing as the present calendar came into use at a time of political changes and religious hatred that stalled its adoption for longer than it should have.
Duncan is especially fluent in describing how the nature of time itself was core to the philosophical schools of Plato, Aristotle and St Augustine and how people like Thomas Aquinas spent considerable intellectual effort reconciling Augustine's formula of God's time and the time of the seasons and man's time.
This book will expand your knowledge.

[Paul Ransom · Rating 4 out of 5]

It is nearly always fascinating to unpack the histories and origins of that which we take mostly for granted. David Ewing Duncan's deep dive into the evolution of the common calendar is a great example of such. In this rivetting book he unpacks the labyrinthine journey humanity has taken not only to agree on a method of quantifying the year and the seasons but to reconcile astronomic and planetary realities with planting/harvesting cycles, religious observance, and other ideo-political and cultural preferences. Whilst this might seem an arcane and obsessive topic, here it comes alive. The style is warm and the ideas clear and easy to keep track of - and all without being dumbed down. Make a note on your calendar to check it out some day.

[Levi Stelljes · Rating 4 out of 5]

It’s not the author’s fault that the Middle Ages just aren’t interesting reading material, but the first 60 pages (6000 BC-325 AD) and the last 70 pages (1400 AD-1999 AD) saved the book for me.

If I could add a day of my life for every time the author used the word Strident, I’d have Britain’s 11 days back.

The Venerable Bede might be my new role model. He also wrote an Easter hymn that we sang in church this morning (on the hopefully correct arbitrary date).

Next U.S. presidential candidate to run under the Calendar Reform Now ticket has my vote locked up. Let’s get this World Calendar cooking.

[Jacob Lehman · Rating 3 out of 5]

Interesting story of how the Gregorian calendar came to be/take over Europe and the world, but some clear editorial lapses (the math doesn't hold up in some places on the number of years in between events or the various calendars running slow/fast).

I read this as part of my project to read one book from every aisle of Olin Library at Cornell; you can read my reactions to other books from the project here: https://jacobklehman.com/

A fuller review/reaction will follow on my website.

[David Szatkowski · Rating 3 out of 5]

Overall, I did like this book. There was some bias; it is hard to both say that the "Church" was blocking science/reform when it's the Church's own clerics and hierarchy pushing the reform, math, and science behind it. At times there is come clear condensation towards past epochs, which is also a bias to be wary of. That said, very readable and recommendable. Whether you like history, calendars, the growth of science, or the Middle Ages, there is something here for you.

[Debi Emerson · Rating 5 out of 5]

In a book that reads like a novel, the author does an excellent job of tracing man's struggle to develop accurate ways to keep track of time, from a caveman's earliest efforts involving scratching hashmarks on a bone through the various calendars used to today's use of an atomic element that ends up actually being a bit TOO accurate. A very interesting & entertaining read!

[Adriana Ortiz · Rating 5 out of 5]

Está libro fue una acogedora sorpresa! Tal como lo dicen algunas reseñas, se trata , no solo del calendario, sino de la historia del hombre y su búsqueda en la medición del tiempo.
A mi me pareció fabuloso. Por qué medidos los días en semanas de 7 días? Porque 24 horas? Por qué arbitrariamente 12 meses y no 10?
Súper recomendable.

[Peggy · Rating 4 out of 5]

Definitely learned things about the way humans have marked time, but the author included so much back story information that didn’t seem necessary. I found myself skimming for the next bit of significant information and felt like much of it didn’t connect and just added to confusion.

[Ann Strautins · Rating 4 out of 5]

From 28,000 BC Cro-Magnon's bone carving calendar till nearly now, c1998. A long journey with fascinating facts but also some slow but probably necessary information sections. If you have ever wondered upon time measurement and how we got to now this is worthwhile reading.

[Audrey · Rating 5 out of 5]

This was Exactly what I was looking for in a book about the creation of our modern calendar. I found it fascinating, entertaining, and an easy read. But if one weren’t interested in this topic… well, take my 5 stars with salt.

[Rizwan · Rating 4 out of 5]

Very detailed but sometimes overly so, with the narrative getting slightly lost.

[Jan van Trigt · Rating 3 out of 5]

Fascinating book abput the journey of mankind on how to define a year and how sun and moon determine "a month". The best counting was done in the middle east. Fun to read.

[Rena · Rating 5 out of 5]

Wonderful! A beautiful exploration into the struggle of humanity to describe time itself. My view of time and the calendar as we know it today will be forever changed.

[Joe · Rating 5 out of 5]

This was a great exposition of the history of how the calendar evolved since ancient times.

[Mrsculpepper · Rating 3 out of 5]

fascinating material but could have used better proofreading/editing. nothing major but a few typos, punctuation errors that were noticable and slightly jarring.

[Elizabeth · Rating 1 out of 5]

DNF