Understanding Date Conventions: The Shift from BC/AD to BCE/CE
When we look back at history, we use specific labels to organize time. For centuries, the most common way to denote years has been using BC (Before Christ) and AD (Anno Domini). However, in recent decades, a different set of abbreviations—BCE (Before the Common Era) and CE (Common Era)—has become increasingly prevalent in academic, scientific, and international contexts.
While these terms might seem like mere linguistic changes, they represent a significant shift in how we approach global history and religious neutrality. This article explores the origins, meanings, and the ongoing transition between these dating conventions.
What is the Difference Between BC/AD and BCE/CE?
At their core, these two systems are mathematically identical. They use the same epoch (the starting point) to measure time. Using the year 2026 as an example, "2026 CE" is the exact same year as "AD 2026." Similarly, "400 BCE" is the same as "400 BC."
The primary difference lies in the terminology used to describe the era:
- AD (Anno Domini): A Latin phrase meaning "in the year of our Lord." It is used to denote years following the birth of Jesus Christ.
- BC (Before Christ): Used to denote the years preceding the birth of Jesus Christ.
- CE (Common Era): A secular alternative to AD, used to provide a neutral way to refer to the same timeframe without explicit religious connotations.
- BCE (Before the Common Era): The secular counterpart to BC.
![Johannes Kepler (1571–1630), the German astronomer, mathematician, astrologer, natural philosopher and writer on music[11]](/images/a5/73/a573ca7bd6864e83a63ec45021fb7c5337ef1aa3a7c2ef7005bdbe284e113e66.jpg)
The Historical Evolution of Dating Terms
The "Vulgar Era" and Johannes Kepler
The concept of a "common" or "vulgar" era has roots in early modern science. The German astronomer and mathematician Johannes Kepler is credited with early uses of the term anno aerae nostrae vulgaris (the year of our common era) in his works published between 1615 and 1617. Kepler’s goal was to distinguish the widely used Anno Domini era from the "regnal years" used in German law, which were based on the reign of a specific sovereign.
The Rise of the "Common Era"
The English phrase "Common Era" began appearing in literature as early as 1708. By the late 18th and early 19th centuries, terms like "vulgar era" and "common era" were often used synonymously in encyclopedias and academic texts. As global scholarship expanded, the need for a designation that was inclusive of non-Christian perspectives grew, leading to the modern popularity of BCE and CE.
Global Usage and Contemporary Trends
The adoption of BCE/CE varies significantly by region and discipline. In the United States, the use of BCE/CE in textbooks has been growing since 2005. Notably, the 2007 World Almanac was the first edition to switch entirely to these notations, ending a 138-year streak of using BC/AD.
Different institutions follow different rules:
- Academic and Religious Studies: The Society of Biblical Literature and many history textbooks prefer BCE/CE to maintain neutrality.
- Media and General Interest: The History Channel uses BCE/CE specifically when discussing non-Christian religious topics, such as Judaism.
- International Standards: In China, the term gōngyuán (Common Era) is used for both internal and external affairs, while in Taiwan, the term xīyuán (Western Era) is used in formal documents.
Summary of Dating Conventions
| System Type | Before Epoch | After Epoch | Primary Context |
|---|---|---|---|
| Traditional/Religious | BC (Before Christ) | AD (Anno Domini) | Religious and traditional historical texts. |
| Secular/Academic | BCE (Before Common Era) | CE (Common Era) | Scientific, academic, and international contexts. |
Key Facts
- Mathematical Equivalence: BCE/BC and CE/AD refer to the exact same years.
- Notation Rule: Unlike AD, which often precedes the year (AD 2026), CE always follows the year (2026 CE).
- Purpose: The shift to BCE/CE is intended to provide a neutral, non-religious framework for global history.
- Early Use: Johannes Kepler used early versions of "common era" terminology in the early 17th century.
Frequently Asked Questions
Why do some people prefer BCE/CE over BC/AD?
The primary reason is to use language that is inclusive of people from various religious backgrounds. By using "Common Era," scholars can refer to the standard global calendar without making an explicit theological claim regarding the "Lord."
Is it grammatically correct to write "AD 2026 CE"?
No. You should use either "AD 2026" or "2026 CE." Using both is redundant because they refer to the same era.
Does the use of CE mean the Christian calendar is being rejected?
Not necessarily. The BCE/CE system maintains the same numbering and epoch as the Christian calendar; it simply changes the labels to be more secular and widely applicable in a globalized world.
How do I write these abbreviations correctly?
Standard convention dictates that BCE and BC always follow the year (e.g., 399 BCE). AD is traditionally placed before the year (e.g., AD 2026), though CE always follows the year (e.g., 2026 CE).
Are there other calendars used instead of the Common Era?
Yes. While the Gregorian/Common Era system is the most widely used globally, other systems exist, such as the Hebrew, Islamic, Chinese, and Maya calendars, each with its own unique epoch and method of tracking time.