Are Ages, Eras, and Historical Time Periods Capitalized?
Summary
Capitalize names given to specific historical periods, but lowercase descriptive terms.
- the Stone Age
- the Renaissance
- the Middle Ages
- the digital age
- the nuclear age
- the modern era
Capitalize proper names in time periods.
- the Victorian era
- the Roman era
Capitalize names of geological periods.
- the Paleolithic
- the Jurassic
Historical periods, eras, and ages
Long, distinct periods in history carry specific names. These time periods are generally bound by historical events or cultural movements and practices. While some cultural periods are well defined (the Victorian era), others are less specific (the digital age). Geological periods in Earth’s history (the Mesozoic) are generally more clearly defined.
- The Renaissance saw the rebirth of European philosophy, literature, and art.
- This book will appeal to people interest in the Middle Ages.
- It is now thought the Dark Ages were not dark at all.
- The novel came into its own in the Victorian era.
- Some believe the end of the digital age is in sight.
- At the start of the Mesozoic, Gondwana was still part of the supercontinent Pangaea.
The general rule
The general rule is to capitalize names of specific historical periods with defined beginnings and endings but to lowercase descriptive terms.
- the Middle Ages
- the Stone Age
- the Renaissance
- medieval times
- the modern age
- the postcolonial era
Years, decades, and centuries are not capitalized when written in words.
- Nineteen twenty-three was a watershed year in motor racing.
- The nineties were a time of immense possibility.
- Sylvia Plath was one of the great poets of the twentieth century.
The capitalization of a time period is often based on tradition. Remember that capitalization is a matter of style rather than grammar. Always follow accepted conventions in your field or area of study. As an editor, you may have to respect the preference of the author.
When to capitalize
Capitalize specific names given to well-defined time periods and events in cultural and social history (like Renaissance, Middle Ages, Dark Ages), as you would other proper nouns.
- the Dark Ages
- the Middle Ages
- the Renaissance
- the Age of Enlightenment
- the Industrial Revolution
- the British Raj
- the Reformation
- the Roaring Twenties
- the Jazz Age
- the Swinging Sixties
When not to capitalize
Avoid capitalizing descriptive terms used for time periods.
- the digital age
- space-age technology
- the nuclear age
- a golden age
- the medieval period
- ancient times
- the modern age
- the postmodern era
- the colonial period
- the postcolonial era
- the age of rock and roll
- sixties music
- hippie-era fashions
- the chat-room era
- the age of capitalism
- the age of materialism
Generic terms
Capitalize names of time periods when necessary to avoid confusion with a generic description.
- the Heroic period
- the Romantic period
- the Golden Age
- the Classical period
The term golden age, when used to speak of a defined period of time, is generally capitalized. But when used as a generic term, it is lowercased.
- The Golden Age of Latin literature lasted from 70 BC to AD 18.
- It was the golden age of rock and roll.
Proper names
Capitalize any proper names in descriptive terms. In such time periods, where capitalization happens only because of a proper noun or adjective, words like era and age are not capitalized.
- the Victorian era
- the Edwardian period
- the Elizabethan era
- ancient Greece
- the Roman empire
- the Mughal era
- the Homeric age
- the Ciceronian period
- the Jacobean age
- the Georgian era
Ages: Ancient
Capitalize names of cultural periods in ancient human history.
- the Stone Age
- the Bronze Age
- the Iron Age
The term ice age refers to any of multiple periods of widespread glaciation in Earth’s geological history. Since the term does not refer to one specific period, it is not capitalized.
- Incorrect: The last Ice Age ended around 11,500 years ago.
Correct: The last ice age ended around 11,500 years ago.
Ages: Modern
Unlike ancient periods in human civilization (like Stone Age), more modern ages and time periods may be either capitalized or lowercased.
- the age of reason or Age of Reason
- the space age or Space Age
- the atomic age or Atomic Age
- the information age or Information Age
Capitalization differs across styles. For example, while the AP Stylebook recommends capitalizing atomic age, in actual usage (e.g., Scientific American), the term is often lowercased. Other terms like information age may be either capitalized or lowercased, depending on preference and field of study. Dictionaries, like Merriam-Webster, list both variants. In general, references to time periods without clearly defined chronological boundaries are not capitalized.
Eras
Abbreviations for eras are written in capital letters, generally without periods.
- Alexander the Great was born in 356 BC.
- Byzantium was renamed Constantinople in AD 330.
- The East India Company was founded in 1600 CE.
- In the fifth century AD, one of my ancestors sailed from India to Java.
The abbreviation BC appears after the year (375 BC), while AD appears before (AD 375).
Geological time periods
Capitalize geological terms for time periods (e.g., Paleolithic, Pleistocene, Mesozoic, Jurassic). Words like era, epoch, and period are generally omitted, and the time period is referred to, for example, simply as “the Pleistocene.”
- The supercontinent, Pangaea, began to break apart in the Early Jurassic.
- Dinosaurs went extinct at the end of the Cretaceous.
- Many species went extinct during the Pleistocene.
- In the Paleolithic, humans were hunters and gatherers.
- Because humans turned to agriculture in the Mesozoic, they began living in stable settlements.
Adjectives used with geological time periods (like early and late) are capitalized when part of a formal term, but lowercased when used merely descriptively.
- the Early Jurassic
- the Upper Cretaceous
- the Middle Cambrian
- the Late Paleozoic
- early in the Jurassic
- in the early Upper Cretaceous
When common nouns like era and epoch are included, they may be either capitalized or lowercased. Style guides differ in their recommendations: the AP Stylebook suggests capitalizing words like epoch when part of a geological term; the Chicago Manual of Style recommends lowercasing.
- the Archaean Eon or the Archaean eon
- the Precambrian Era or the Precambrian era
- the Jurassic Epoch or the Jurassic epoch
In geologic time, stages make epochs, epochs form periods, periods make eras, and eras combine to form eons. Try not to use the inexact term period to cover all geological time periods.
- Poor: With dinosaurs gone, plant life flourished in the Cenozoic period.
Better: With dinosaurs gone, plant life flourished in the Cenozoic era.
Best: With dinosaurs gone, plant life flourished in the Cenozoic.
For a useful overview of geological periods, see Merriam-Webster’s entry on geologic time.