Historical chronology: What you need to know

© History Skills

The very first step in grasping History is to understand chronology.


Chronology in history refers to the arrangement of events in the order in which they occurred. It is the study of how time is organised and divided in relation to historical events.


The goal of chronology in history is to place events in their proper order, so that they can be studied and understood in their historical context. 


There are several rules that have been developed over time to achieve this and they are outlined below. The terms and concepts outlined here can be used in your own historical writing to improve your academic vocabulary.

How time is ordered in history

The measurement of time is traditionally based around the birth of Jesus Christ.
  • For events that occurred before Jesus’ birth, type ‘BC’ (an abbreviation for ‘Before Christ’) after the number of the year.
    • For example: 48 BC.
  • For events that happened after Jesus’ birth, type ‘AD’ (an abbreviation for the Latin phrase anno domini, which means “Year of our Lord”) before the number of the year.
    • For example: AD 120.
 For those who prefer a non-religious version, the following alternatives are placed after the number of the year:
  • BCE (Before Common Era) = BC

    • For example: 48 BC becomes 48 BCE
  • CE (Common Era) = AD

    • For example: AD 120 becomes 120 CE

Watch a video explanation on the History Skills YouTube channel:

Watch on YouTube

Additional notes regarding dates:
  • If there isn’t a ‘BC’ or ‘AD’ next to a date, it is probably AD

  • Before the birth of Christ, the number of years counts down, but after that, the years count upwards

  • There is no year ‘0’: the year 1 BC is followed immediately by AD 1

  • ‘BP’ after a number stands for ‘Before the Present’

  • ‘Circa’ means ‘around about’ and is a small ‘c.’ before the year. For example: c. 50 BC

How time is divided

Since human history has occurred over tens of thousands of years, historians have had to develop a system to help them talk about large sections of time easily.


As a result, names are given to groups of years. The groups and their names are as follows:

  • Decade               = 10 years
  • Century              = 100 years

  • Millennium       = 1000 years

Watch a video explanation on the History Skills YouTube channel:

Watch on YouTube

Therefore, time can be split into centuries or millennia, as is demonstrated below:

Years Century Millennium
 1000-901 BC 10th century BC 1st millennium BC
900-801 BC 9th century BC
800-701 BC 8th century BC
700-601 BC 7th century BC
600-501 BC 6th century BC
500-401 BC 5th century BC
400-301 BC 4th century BC
300-201 BC 3rd century BC
200-101 BC 2nd century BC
100-1 BC 1st century BC
AD 1-100 1st century AD 1st millennium AD
AD 101-200 2nd century AD
AD 201-300 3rd century AD
AD 301-400 4th century AD
AD 401-500 5th century AD
AD 501-600 6th century AD
AD 601-700 7th century AD
AD 701-800 8th century AD
AD 801-900 9th century AD
AD 901-1000 10th century AD
AD 1001-1100 11th century AD 2nd millennium AD
AD 1101-1200 12th century AD
AD 1201-1300 13th century AD
AD 1301-1400 14th century AD
AD 1401-1500 15th century AD
AD 1501-1600 16th century AD
AD 1601-1700 17th century AD
AD 1701-1800 18th century AD
AD 1801-1900 19th century AD
AD 1901-2000 20th century AD
AD 2001-present day 21st century AD 3rd millennium AD

Historical periods

To make sense of the past, it is divided into even larger blocks of time called ‘periods’.


Each of these ‘periods’ can be broken down further into smaller times called ‘ages’ and even into smaller times called ‘eras’.

Time Period Ages Eras Approximate Years


(The time before humans had developed writing)


Stone Age Palaeolithic c. 2,500,000 - 6000 BC
Mesolithic 6000 - 4000 BC
Neolithic 4000 - 3000 BC
Bronze Age Early Bronze Age 3000 - 2100 BC
Middle Bronze Age 2100 - 1550 BC
Late Bronze Age 1550 - 1200 BC
Iron Age Iron Age 1200 - 800 BC


(From the time humans began writing until now)


Classical Age Greek Era 800 - 400 BC
Macedonian Era 400 - 300 BC
Hellenistic Era 300 - 146 BC
Roman Era 146 BC - AD 476
Middle Ages Early Middle Ages AD 476 - 1000
High Middle Ages AD 1000 - 1300
Late Middle Ages AD 1300 - 1450
Modern Age The Renaissance AD 1450 - 1600
Age of Discovery AD 1600 - 1750
Industrial Revolution AD 1750 - 1900
Modern Era AD 1900 - Present Day

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Additional resources

Looking for a digital timeline resource?

Timeline Creator (Years)
A nifty Microsoft Excel spreadsheet that allows the user to enter years and sort events by categories. The spreadsheet maps out the events by category in a tabled view that allows the user to see the relationship between the events. Simple y ... (Read More)