What does A.D. mean? - dating system explained
Welcome to Quatr.us Study Guides!

What does A.D. mean?

May 2016 - A.D. stands for Anno Domini, which is Latin for "year of our Lord," and it means the number of years since the birth of Jesus Christ. That was a little more than 2000 years ago, so the date 500 A.D. means a little more than 1500 years ago.

Some people use C.E. instead. That stands for Common Era, and people use it in order to avoid Christian references. Quatr.us feels that since this is a Christian dating system, we don't want to try to hide that. There are other dating systems in the world that non-Christians use, and Common Era makes it sound like everyone should use the Christian system.


Keep track of time with this great Panda Planner!

Of course nobody used the birth of Jesus as a way to count years back when Jesus was alive, in the Roman Empire. The Romans mostly counted by emperors: "in the fifth year of the Emperor Augustus," or "in the second year of the Emperor Tiberius." Sometimes the Romans counted by Olympiads - how many years it had been since the first Olympic Games in 776 BC. Or they counted from the (mythical) date of the foundation of the city of Rome, in 753 BC. Many Romans were afraid the world would end in the year 1000 (1000 years since the founding of the city of Rome, which we call 247 AD), and the first big Roman persecution of Christians grew out of that fear.

As people converted to Christianity, though, they wanted to count their years by Christian events and not Greek festivals or Roman emperors. Not long after the fall of Rome, in 525 AD, a few Christian priests and bishops began to count from the birth of Jesus. But most people in Europe didn't start to use this Christian calendar until about 800 AD, in the time of Charlemagne.

In the 1800s, Christian history researchers taking a closer look at the Bible realized that they had the year of Jesus' birth wrong. Because King Herod died in 4 BC, the birth of Jesus had to be about four to six years earlier than everyone had thought. But it was too hard to change the system now, so we still count from the Year 1 (there is no Year 0), even though Jesus was already walking and talking by then.

As Europeans gradually conquered more and more of the world after 1500 AD, they brought their calendar with them. So people began to use the Christian calendar in Africa and India around 1500 AD, in North and South America a few years later, and in China and Japan only around 1900 AD, about a hundred years ago.

More about the birth of Jesus
More about BC and AD

Bibliography and further reading about history timelines:

Find out about B.C. or B.C.E.
Quatr.us home

Decorative timelines for your classroom:

This one is American history


and this one is African-American history:

It's harder to do all of World History in one chart:

but this World History timeline sums it all up.



A timeline game to play - more fun than flash cards!

LIMITED TIME OFFER FOR TEACHERS: Using this article with your class? Show us your class page where you're using this article, and we'll send you a free subscription so all your students can use Quatr.us Study Guides with no distractions! (Not a teacher? Paid subscriptions are also available for just $16/year!)
Please help other teachers and students find us: link to this page from your class page.
Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram or Twitter, or buy her book, Vandals to Visigoths.
Cite this page
  • Author: K.E. Carr
  • Title:
  • Site Name: Quatr.us Study Guides
  • Publisher: Quatr.us
  • Date Published:
Did you find what you needed? Ask your teacher to link to this page so other people can use it too! Send it in and win a Quatr.us "Great Page!" award!
Sign up for more free articles and special offers in Quatr.us' weekly newsletter:
We will never share your e-mail address unless you allow us to do so. View our privacy policy. Easy unsubscribe links are provided in every email.
Comment on This Article

Does your class page honor diversity, celebrate feminism, and support people of color, LBGTQ people, and people with disabilities? Let us know, and we'll send you a Diversity Banner you can proudly display!
Looking for more?
Quatr.us is loading comments...
(Comments will appear after moderation, if they are kind and helpful. Feel free to ask questions, and we'll try to answer them.)
Cite this page
  • Carr, K.E. . Quatr.us Study Guides, . Web. 27 April, 2017
ADVERTISEMENT