Comprehensive Guide to Chronology and Periodization

Definition of Chronology: Chronology is defined as the arrangement of events in the sequential order of their occurrence.
Pre-History: This term refers to any history that occurred before the creation of a writing culture.
History: This period begins from the time that people developed writing, which occurred approximately $5000$ years ago.

History is further categorized into distinct sequential periods: * Ancient History * The Dark Ages * The Middle Ages * Modern History

Century Definition: Centuries are intervals of $100$ years used by historians to divide long periods in history.
Calculating the Century: To determine which century a specific year belongs to, use the following rules of addition: * For a year consisting of $3$ digits: Add $+1$ to the first digit. * For a year consisting of $4$ digits: Add $+1$ to the first two digits.
Examples of Century Calculation: * For the year $476\,BCE$ : Take the first digit ( $4$ ) and add $1$ ( $4 + 1 = 5$ ). This is the $5^{th}$ Century. * For the year $1066\,CE$ : Take the first two digits ( $10$ ) and add $1$ ( $10 + 1 = 11$ ). This is the $11^{th}$ Century.

Purpose: Historians use periodization to simplify the vast amount of time covered by history by dividing the past into two primary eras.
Christian Era System: Uses the designations Before Christ ( $BC$ ) and Anno Domini ( $AD$ ) to distinguish the two periods.
Non-Christian Era System: Uses the designations Before the Common Era ( $BCE$ ) and Common Era ( $CE$ ).
Rule of Usage: A historian may not use both systems appearing on a single timeline simultaneously.
The Division Point: The separation between the two eras is marked differently depending on the system used: * Christian Timeline: The division is indicated with a " $t$ ". * Non-Christian Timeline: The division is left blank. * Strict Prohibition: Never, ever use a " $0$ " to indicate the division point between eras.

Definition of Periods: Time is further subdivided into specific periods identified by a common unifying idea or a dominant event of that era.
Examples of Identified Periods: * The French Revolution * The Cold War * The Age of Enlightenment