Here are three guidelines that will help you determine when to capitalize historical time periods.
Capitalization guidelines for historical time periods are influenced by tradition and whether they are named after a proper noun. As with all things influenced by tradition, these guidelines can change according to where you live—or in this case, which style guide or dictionary you follow. So, please consult your style guide or dictionary if it doesn’t appear in the reference list or if you are writing about historical time periods not shown in the examples below.
1. Capitalize Prehistoric and Traditional Archeological Time Periods
Prehistoric and traditional archeological time periods are normally capitalized:1
The Ice Age ended approximately 12,000 years ago.*
Humans became avid tool makers during the Stone Age.
Early writing systems developed during the Bronze Age.
During the Iron Age, metalworking techniques improved, leading to higher quality weapons.
The Dark Ages were rather gloomy.
The Middle Ages are made up of three periods called the Early Middle Ages, the High Middle Ages, and the Late Middle Ages.
The Renaissance was a time of artistic, cultural, and intellectual advancements.
*Writers who follow The Associated Press Stylebook (AP) should lowercase Ice Age.2
2. Capitalize Historical Time Periods Named after a Proper Noun
Historical time periods named after a proper noun, such as a person (e.g., Queen Elizabeth) or specific people (e.g., the Vikings), are typically capitalized.3 However, the second noun in the phrase (e.g., era, age, or period) is lowercased:
The Viking age was propelled by the Scandinavians’ exceptional ship-building skills.
William Shakespeare wrote his plays during the Elizabethan era.
The Victorian era is named after Queen Victoria, who reigned for over sixty-three years.
The Seinfeld era, which lasted from 1989 to 1998, gave us the secular holiday Festivus. (Okay, the Seinfeld era isn’t an official historical time period—yet.)
3. Lowercase Most Other Historical Time Periods—But Check Your Dictionary when Questions Arise!
Most other historical time periods that aren’t named after proper nouns or directly associated with specific decades (e.g., the Roaring Twenties, the Great Depression) are lowercased, but check your dictionary for variations. In many cases, dictionaries list lowercased and capitalized versions, in which case you should choose one format to use consistently throughout your document.** Capitalization of the second noun in the phrase (e.g., era, age, or period) also varies by source:
Chairs from the colonial period are prized by antique collectors.4
The baroque period began in the late sixteenth century and lasted until the early eighteenth century.5
The Gilded Age is named after a Mark Twain novel.6
We are currently living in the information age.7
**Writers who follow The Associated Press Stylebook (AP) should choose the lowercase format when both versions are acceptable.8
Visit “How to Write Decades as Words and Numerals” and “How to Write Centuries as Words and Numerals” for more timely writing advice.
References
1. The American Heritage Dictionary of the English Language, 5th ed.; The Associated Press Stylebook 2020–2022 (New York: Associated Press, 2020), 141–42; The Chicago Manual of Style, 17th ed. (Chicago: University of Chicago Press, 2017), 8.73–74; Merriam-Webster’s Collegiate Dictionary, 11th ed.; Webster’s New World College Dictionary, 5th ed.
2. The Associated Press Stylebook 2020–2022 (New York: Associated Press, 2020), 148.
3. The American Heritage Dictionary of the English Language, 5th ed.; The Associated Press Stylebook 2020–2022 (New York: Associated Press, 2020), 141–42; The Chicago Manual of Style, 17th ed. (Chicago: University of Chicago Press, 2017), 8.72; Merriam-Webster’s Collegiate Dictionary, 11th ed.; Webster’s New World College Dictionary, 5th ed.
4. The American Heritage Dictionary of the English Language, 5th ed.; The Associated Press Stylebook 2020–2022 (New York: Associated Press, 2020), 56; The Chicago Manual of Style, 17th ed. (Chicago: University of Chicago Press, 2017), 8.72; Merriam-Webster’s Collegiate Dictionary, 11th ed.; Webster’s New World College Dictionary, 5th ed.
5. The American Heritage Dictionary of the English Language, 5th ed.; The Chicago Manual of Style, 17th ed. (Chicago: University of Chicago Press, 2017), 8.72; Webster’s New World College Dictionary, 5th ed.
6. The American Heritage Dictionary of the English Language, 5th ed.; The Chicago Manual of Style, 17th ed. (Chicago: University of Chicago Press, 2017), 8.73; Webster’s New World College Dictionary, 5th ed.
7. The American Heritage Dictionary of the English Language, 5th ed.; The Chicago Manual of Style, 17th ed. (Chicago: University of Chicago Press, 2017), 8.74.
8. The Associated Press Stylebook 2020–2022 (New York: Associated Press, 2020), 141–42.