Using Timelines

Timelines show the passage of time as a line.
Events are organized in the order they occurred.
They work like number lines.

Chronology - the order in which events occur

​Dates in Ancient History

In ancient history, years are written with abbreviations.

A year followed by B.C. refers to the number of years before the birth of Christ.

A year preceded by A.D. refers to the number of years after the birth of Christ.

Historians also use B.C.E. (Before Common Era) and C.E. (Common Era) for these periods.

PSA: the year AD 1 happened immediately after 1 BC. There is no year 0!

​Other ways to break up time

You'll see the following to describe different chunks of time:
Decade: 10 years
Century: 100 years
Millennium: 1000 years

Sometimes, the language of history isn't as precise. The following words mean:
Epoch: a period of time which begins with a significant event
example: the invention of the internet set off a new epoch in technology
Era: a period of time which is marked by a something new
example: in the era of social media
Age: a period of time defined by a person or event
example: in the age of exploration

Records of historical period or event created by someone who was not there or did not participate in the event or time period

​Secondary - 2nd hand

Original records of a specific historical period
Produced by people who participated in or witness an event

​Primary - 1st hand

Historical Sources

Bias and Reliability

All sources have bias. It is the historian's job to identify bias and see past it to the "truth."

All sources must be tested for reliability. Can your information be trusted? Should it be taken with a "grain of salt" or ignored completely?

Bias: preference for one side/view point over another

Reliability: trustworthy, accurate