Time periods and events are capitalized when they refer to specific periods or use proper nouns in the title, e.g., the Roaring Twenties or the American Civil War. Time periods are not capitalized when they refer to nonspecific events or a general time period, such as centuries or decades, e.g., the twenties or a civil war.
Below, we explain the capitalization rules for history, as well as when to capitalize periods and events and when not to, with plenty of examples.
Capitalization for archaeological and geological periods
Archaeological and geological periods are capitalized when referred to by name, as in these examples:
- eons (the Phanerozoic Eon)
- eras (the Mesozoic Era)
- periods (the Jurassic Period)
- epochs (the Holocene Epoch)
- ages (the Bronze Age)
Notice that both words are capitalized in the names of these time periods because they’re proper nouns.
Keep in mind that ages can also be used generally when they do not refer to a specific period of time, but rather to a broad description of conditions that can be attributed to different times.
For example, when we talk about the Ice Age, we’re referring to the specific period of time from about 115,000 to 12,000 years ago. Because it’s specific, we capitalize it. However, there were other ice ages. When we talk about ice ages in general, we don’t capitalize them because they’re not proper nouns.
There were many ice ages before the Ice Age.
Additionally, age can be used as an adjective to describe technologies or cultural adaptations indicative of a time. When used as an adjective, we do not capitalize age.
In the Stone Age, everyone used stone-age tools.
Capitalization for historical periods named after a proper noun
To refer to a period of time in human history that focuses on a specific person, nationality, or culture, capitalize the proper noun but not the name of the period. Follow the same rules for the capitalization of countries, nationalities, and languages.
Why is this different from archaeological and geological periods? In the sciences, the geological periods are official, so terms like era and age are part of the name. But it’s worth noting that some style guides disagree on this point. For instance, the Chicago Manual of Style says, “The generic terms ‘eon,’ ‘era,’ and the like are lowercased or omitted immediately following a formal name.” So in Chicago, it would be “the Mesozoic era,” etc. However, periods named after people or cultures are less official and more general—the only reason they’re capitalized at all is because of the proper noun.
Rules for capitalization of periods and events
The basic rule for the capitalization of periods and events is to capitalize specific names but not general terms.
If a general time period uses a proper noun, capitalize only the proper noun. Typically, these refer to periods of human history, as opposed to geological and archaeological periods, in which words like era or age are part of the name.
the Victorian age
However, some periods of human history have “official” names. If words like era or age are part of their formal name, they’re also capitalized.
the Iron Age
the Middle Ages
the Age of Exploration
The nicknames for periods of human history also count as formal names, so they, too, are capitalized.
the Meiji Restoration
General time periods, such as decades and centuries, are not capitalized unless they’re referred to by a specific name.
the nineteenth century
the trial of the century
the Dirty Thirties
When it comes to historical events, capitalization becomes more complicated. The basic rule still applies: Capitalize the name of a specific historical event, but don’t capitalize events used in a general sense.
the Second World War
There were two world wars in the 1900s.
The Industrial Revolution was not a political revolution but a technological revolution.
Keep in mind that the names of historical events follow the same rules as capitalization in titles. Articles, conjunctions, and prepositions are not capitalized unless they’re the first word.
the Siege of Baghdad
the Battle of the Ten Kings
the Anarchy at Samarra
Summary: When to capitalize and when not to capitalize
When to capitalize
- geological and archaeological periods (the Mesozoic Era)
- names of historical periods (the Revolutionary Period)
- names of historical events (the Black Death)
- proper nouns when describing periods (the Vedic period)
When not to capitalize
- nonspecific events (a civil war)
- decades, centuries, and other general time periods (the nineties)
Capitalization: Periods and events examples
When writing, people come across the same problems with capitalizing historical periods and events. Below are some of the most common questions we’ve been asked about capitalization, along with their correct answers. If your specific question isn’t here, go ahead and use our free grammar checker.
Is history capitalized?
The word history is capitalized only when it’s part of a proper noun, such as a museum name or the title of a specific class.
I love history, so I joined the History 101 class when it went to the National Museum of American History.
Is medieval capitalized?
The word medieval is not capitalized. It is used as an adjective, not a proper noun. It still follows the normal rules of capitalization, though, so you would capitalize it as part of a title, as in The Book of Medieval Art.
Is renaissance capitalized?
The word renaissance can refer to either a general period of revival or a specific period of European history. It is not capitalized when used generally, but it is capitalized when referring to the specific European period.
The most famous renaissance was probably Europe’s Renaissance.
Is civil rights movement capitalized?
The phrase civil rights movement is not capitalized because it is not a proper noun. It’s an umbrella term that refers to multiple events rather than one specific event. However, the Civil Rights Act of 1964 is capitalized because it’s the title of a specific law.
Is civil war capitalized?
The phrase civil war is not capitalized when used in the general sense. However, if you’re referring to a specific civil war by name, then it is capitalized.
Many civil wars erupted during the Arab Spring, and the Syrian Civil War is ongoing.
When should you capitalize a time period or event?
Time periods and events are capitalized when they refer to specific periods or use proper nouns in their titles, e.g., the Roaring Twenties or the American Civil War.
When should you not capitalize a time period or event?
Time periods are not capitalized when they refer to nonspecific events or a general time period, such as centuries and decades, e.g., the twenties or a civil war.
What are some examples of historical periods that should be capitalized?
Any historical period with a formal name is capitalized, such as the Industrial Revolution or the Meiji Restoration.
What are some examples of historical periods that should not be capitalized?
General time periods, including decades and centuries, are not capitalized, such as the eighties or the twentieth century.