Human history is vast, and to study it systematically, scholars created systems to measure and divide time. One of the most widely used systems is the BC and AD timeline, which divides history into two major eras centered around the birth of Jesus Christ. This system, first developed in the early medieval period, continues to be a global standard, though modern alternatives like BCE and CE are now often used.
The traditional system uses two abbreviations to mark time:
This system was created by a monk named Dionysius Exiguus in the 6th century AD. It was not immediately adopted but gained widespread use across Europe in the Middle Ages. The system has no “year zero”; the year 1 BC is followed directly by the year 1 AD.
The BC/AD system was introduced in the 6th century by a monk named Dionysius Exiguus, who wanted to calculate the date of Easter. He chose to base his calendar around what he believed was the year of Christ’s birth. Over time, this system became the standard across Christian Europe and later spread globally through European influence.
In recent years, many historians, academics, and publishers have adopted a different system that avoids religious references. This system uses the same timeline but with different labels:
The Common Era is a secular term that refers to the most commonly used calendar system in the world today, the Gregorian calendar. Using BCE/CE allows for historical dating that is universally accessible and respectful of different cultures and beliefs.
The two systems are identical in their numerical values; only the abbreviations are different.
Both systems serve the same purpose: providing a clear, chronological framework for understanding historical events. While BC/AD is still common, you will increasingly find BCE/CE in academic texts and museum exhibits.
The BC/AD system has served as a universal timeline for centuries, helping us make sense of human history across different eras. While BCE and CE are now more commonly used for inclusivity, the foundation remains the same. Whether one uses BC/AD or BCE/CE, this timeline is essential for understanding the past and connecting civilizations through a shared historical framework.
Q: What does BC stand for?
A: BC stands for Before Christ.
Q: What does AD stand for?
A: AD stands for Anno Domini, Latin for “In the Year of Our Lord.”
Q: Does AD mean “After Death”?
A: No. AD means Anno Domini, not “After Death.”
Q: What does BCE mean?
A: BCE means Before Common Era, a modern alternative to BC.
Q: What does CE mean?
A: CE means Common Era, a modern alternative to AD.
Q: Is BCE/CE the same as BC/AD?
A: Yes, they represent the same timeline but are non-religious terms.
Q: Who created the BC/AD system?
A: A monk named Dionysius Exiguus in the 6th century.
Q: Why was the BC/AD system created?
A: It was designed to calculate the date of Easter and organize history around the birth of Jesus Christ.
Q: Is there a year zero in BC/AD?
A: No, the system goes directly from 1 BC to AD 1.
Q: What year is it now in BC/AD?
A: In 2025, it is AD 2025 (or 2025 CE).
Q: If something happened in 300 BC, how many years before AD 1 was it?
A: It happened 300 years before AD 1.
Q: What is the first year of the AD era?
A: AD 1 is the first year.
Q: How is 500 BCE different from 500 BC?
A: They are the same year; only the terminology is different.
Q: Why do historians use BCE/CE instead of BC/AD sometimes?
A: Because BCE/CE are more inclusive and non-religious terms.
Q: When did BC/AD dating become common in Europe?
A: It became common during the Middle Ages.
Q: What calendar is BC/AD based on?
A: It is based on the Gregorian calendar (and earlier the Julian calendar).
Q: Was Jesus actually born in AD 1?
A: Most scholars believe Jesus was born a few years earlier, around 4–6 BC.
Q: How do we date events before BC/AD was invented?
A: Historians retroactively applied the system to earlier events.
Q: What is older: 2000 BC or 1000 BC?
A: 2000 BC is older.
Q: How do we count years in BC?
A: They count backward: 300 BC is earlier than 200 BC.
Q: Which era covers most of recorded human history: BC or AD?
A: BC covers longer human history, but AD covers the modern era.
Q: What does “Anno Domini” literally translate to?
A: It means “In the year of the Lord.”
Q: Is BC/AD used worldwide?
A: Yes, it is widely used globally, though many prefer BCE/CE today.
Q: Can BC/AD be used in science?
A: Yes, but scientists often prefer BCE/CE for neutrality.
Q: Why is understanding BC/AD important?
A: It helps us place events in chronological order and understand world history better.
Q: In which century was the BC/AD system created?
A: The 6th century AD.
Q: In the BC system, do dates count forward or backward?
A: They count backward (e.g., 200 BC is earlier than 100 BC).
Q: In the AD system, do dates count forward or backward?
A: They count forward.
Q: Is there a “year zero” in the BC/AD system?
A: No, the year 1 BC is followed directly by the year 1 AD.
Q: Why did many historians and academics adopt the BCE/CE system?
A: To use a more secular and universally accessible system that avoids religious references.
Q: What is the numerical relationship between BCE/CE and BC/AD?
A: They are identical in their numerical values; only the abbreviations are different.
Q: What does the “Common Era” refer to?
A: The most commonly used calendar system in the world today, the Gregorian calendar.
