Capitalizing Age Names, Time Periods, and Centuries

Capitalization rules are often tricky and they can vary depending on what style you follow. Here are some examples of how to capitalize the names of historical periods (such as the Roaring Twenties) and century names.

Mignon Fogarty

capitalizing centuries

Ages and time periods with specific names are capitalized: 

  • the Bronze Age
  • the Middle Ages
  • the Jazz Age
  • the Roaring Twenties 
  • the Renaissance

On the other hand, if the name is simply descriptive, keep it lowercase. Examples from the AP Stylebook and the Chicago Manual of Style that stay lowercase except for the name of the country include 

  • ancient Greece 
  • classical Rome 
  • the colonial period 
  • the antebellum period 

Centuries Stay Lowercase

When you’re writing about centuries, the words remain lowercase; however, there is a difference between AP and Chicago style: 

  • 17th century (AP style)
  • seventeenth century (Chicago style)


“Centuries.” Chicago Manual of Style online, 16th edition. 9.33. http://www.chicagomanualofstyle.org/16/ch09/ch09_sec033.html (subscription required, accessed January 22, 2015).

“Descriptive designations for periods.” Chicago Manual of Style online, 16th edition. 8.71. http://www.chicagomanualofstyle.org/16/ch08/ch08_sec071.html (subscription required, accessed January 25, 2015).

“Traditional period names.” Chicago Manual of Style online, 16th edition. 8.72. http://www.chicagomanualofstyle.org/16/ch08/ch08_sec072.html (subscription required, accessed January 22, 2015).

“historical periods and events.” AP Stylebook online. http://www.apstylebook.com/online/?do=entry&id=1428&src=AE (subscription required, accessed January 22, 2015).

About the Author

Mignon Fogarty

Mignon Fogarty is the founder of the Quick and Dirty Tips network and creator of Grammar Girl, which has been named one of Writer's Digest's 101 best websites for writers multiple times. The Grammar Girl podcast has also won Best Education Podcast multiple times in the Podcast Awards, and Mignon is an inductee in the Podcasting Hall of Fame. Mignon is the author of the New York Times best-seller "Grammar Girl's Quick and Dirty Tips for Better Writing" and six other books on writing. She has appeared as a guest on the "Oprah Winfrey Show" and the "Today Show" and has been featured in the New York Times, Business Week, the Washington Post, USA Today, CNN.com, and more. She was previously the chair of media entrepreneurship in the Reynolds School of Journalism in Reno, NV. She hates the phrase "grammar nazi" and loves the word "kerfuffle." She has a B.A. in English from the University of Washington in Seattle and an M.S. in biology from Stanford University. Mignon believes that learning is fun, and the vast rules of grammar are wonderful fodder for lifelong study. 

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