• Skip to main content

History Education

Classroom Information

  • About
    • Jack Le Moine
    • Privacy Policy
  • Fundamentals of History
    • BC/AD Versus BCE/ACE
    • Prehistory
    • Great Ages of History
    • What Are Civilizations?
    • Military Terms
      • Military Operations
      • Branches of Military Science
      • Units and Their Commanders
    • Big Themes of History
  • Courses
    • The Big Courses
      • Big History
      • Big Civilization
      • Big Future
    • By Century
      • Ancient Centuries Before 400 BC
      • Classical Centuries 400 BC to 300 AD
      • The Dark Centuries 300 to 1000
      • The Medieval Centuries 1000 to 1500
      • The Century of the 1500’s
    • By Lifetime
      • Big Colonizing Decades 1600-1670
      • France’s Big Decades 1670-1740
      • Big Decades of Enlightenment and Revolution 1740-1805
      • Europe’s Best Decades 1805-1875
      • Decades of Biggest Change 1875-1945
      • The Most Recent Decades 1945-2020
  • Library
  • Donate

BC/AD Versus BCE/ACE

Once upon a time, there was a monk named Dionysius Exiguus. He decided to calculate the exact year that Jesus Christ was born. He calculated that it was 525 years before his year at the time.

That year of Jesus Christ’s birth became the focal point for numbering the years. Every after that point was called “The year of our Lord” (“anno domini” in Latin). Every year before that was called “Before Christ”. Historians used the abbreviations “AD” and “BC”. Everything was fine and this numbering system of identifying the years in history was widely used.

But there was a problem. Modern scholars checked blank’s math and found out that blank had been four years off. According to blank’s numbering system Jesus Christ was born in the year 4 BC. By this time blanks numbering system had been so widely used that it was just too disruptive to revise the year numbers. So, blanks numbering system remained and it remains in effect today

Then came another problem. A couple of generations ago historians decided that the numbering system was too Christian. After all it was based on the life of Jesus Christ. So, they decided to remove the terms “Anno Domini “ and “Before Christ” and replace them with “After Common Era” (ACE) and “Before Common Era”. So, what was the common era? Well, it turns out that this is just a fictional construct in order to get around the Christianity of the year numbers.

My view is that history is hard enough to remember without having to learn fictional concepts, too. Whatever the problems with having a numbering system based on Jesus Christ’s birth, at least you have a numbering system which attempts to be based on something historical. That’s why we’re sticking to the traditional system of numbering the years.


Prehistory
Real vs Legendary Persons
Great Ages of History
What Are Civilizations?
Military Terms
Big Themes of History


Our History Websites

History Moments History Education
African History American History Ancient History
British History Byzantine History Canadian History
Christian History Current History Cultural History
Diplomatic History Economic History Explorers
French History German History Greek History
Holy Roman Empire India History Italian History
Jewish History Latin American History Medieval History
Mideast History Military History Oriental History
Ottoman Empire Roman History Russian History
Scandinavian History Science History Spanish History
The Old West Cold War History World War II
The Space Age Entertainment and Sports Lands Down Under
Pre-History

Back to the Fundamentals Homepage

Left Arrowback to Big Civilization

  • Day Job: The Chessmaster of CPA Firms
  • Bookkeeping, too
History is Fun!

Copyright © 2026 · Jack Le Moine · Log in