Why Don't Our History Timelines Agree? (And Other Chronology Mysteries Solved)

If you have ever opened two different homeschool history books to the same chapter and ended up with completely different dates, you are not alone.

Take ancient Jericho, for instance. Open an archaeology-based spine, and you’ll see the first stone walls dated around 8000 to 8500 BC. But pick up a Young Earth creationist spine, and you’ll find early post-Flood settlements dated after 5000 BC (or closer to 2500–2000 BC).

Did someone make a glaring typo? Not at all! Ancient history is full of differing viewpoints, historical traditions, and a few quirky calendar rules. Let’s break down why this happens—and how to make sense of it on your timeline.

1. Different Lenses: Archaeology vs. Biblical Chronologies

The biggest reason dates differ comes down to the framework the author uses:

Young Earth & Biblical Spines: Books like The Mystery of History or Diana Waring’s History Revealed anchor their timelines in biblical genealogies, often following Bishop James Ussher’s famous 17th-century calculations. Under this timeline, Creation took place around 4004 BC and the Flood around 2348 BC. That means human cities simply couldn't exist before roughly 2300 BC.
Classical & Secular Spines: Spines like Susan Wise Bauer’s The Story of the World or DK reference books lean on archaeological excavation layers, carbon dating, and pottery styles, which place early agricultural towns like Jericho thousands of years earlier.

Neither author is necessarily "careless"—they are just reading history through different interpretive lenses!

2. Making Sense of Centuries: AD vs. BC

Ever watch your student's eyes glaze over when you explain that the American Civil War happened in the 19th century, but the years start with 18?

The trick is remembering that centuries are ordinal counts—they name the century we are currently counting through, not the ones already finished.

Think of it like a birthday cake:

When a baby is born, they are living in their first year of life, even though they are zero years old.
When they turn 18, their 18th year is in the books—they are now living through their 19th year.

It works the exact same way on the calendar:

1st Century AD: Years 1 to 100
19th Century AD: The 1800s (Years 1801–1900)
21st Century AD: The 2000s (where we are right now!)

What About BC Centuries?

Here is where the lightbulb usually goes off for students: BC dates count backwards toward zero, but the century logic is identical!

The 1st Century BC counts down from 100 BC to 1 BC.
The 5th Century BC (the Golden Age of Greece) covers the 400s BC (500 BC down to 401 BC).
The 8th Century BC covers the 700s BC (800 BC down to 701 BC).

Just like the 19th century AD is the 1800s, the 5th century BC is the 400s BC. Because we are counting down toward the start of the era instead of up, the "century number" is always one step ahead of the "hundreds digit."

3. BC/AD vs. BCE/CE: What’s the Difference?

While browsing through living books and museum websites, you will also notice two different sets of labels:

BC / AD: The traditional Christian dating system. BC stands for Before Christ, while AD stands for the Latin phrase Anno Domini ("in the year of our Lord").
BCE / CE: The secular dating convention. BCE stands for Before Common Era, and CE stands for Common Era.

The key thing to know is that the dates themselves are identical. 500 BC is the exact same year as 500 BCE, and 2026 AD is the exact same year as 2026 CE. The newer labels were introduced to provide a religiously neutral alternative for international and academic use, but the timeline grid remains completely unchanged.

At Living Book Timelines, our timeline cards use the traditional BC / AD designation, keeping in harmony with classic literature and traditional living books.

4. The Mystery of the Missing "Year Zero"

When moving from BC to AD, it feels natural to expect a Year 0 in the middle. But on a history timeline, there is no Year 0. You jump straight from 1 BC to AD 1.

Why? Back in 525 AD, a monk named Dionysius Exiguus created the Anno Domini system to calculate the dates for Easter. At the time, Rome used Roman numerals—and Roman numerals didn't have a symbol or concept for zero! To Dionysius, year numbers were simply counters: 1 BC was the final year before Christ’s birth, and AD 1 was the very first year of the new era.

(Bonus math tip: Because there’s no zero, the time between 2 BC and AD 2 is actually 3 years, not 4!)

How Living Book Timelines Handles the Dates

With all these competing theories, how do you handle dates without confusing your kids?

At Living Book Timelines, we keep things simple: we use the exact timeline found in the book for that specific set of timeline cards.

Whether your family is reading The Story of the World, diving into Genevieve Foster’s Augustus Caesar’s World or George Washington's World, exploring British history with Our Island Story, or reading about heroes of faith in Trial and Triumph, the cards match the dates and chapters of the spine in your hands.

That way, your timeline seamlessly mirrors your daily reading—letting your kids connect the dots without any calendar headaches along the way!