Specific periods, eras, historical events, etc.: these should all be capitalized as proper nouns. Why? Since there are many periods, eras, wars, etc., the capital will differentiate the specific from the common. Consider the examples below:
Most of the World War I
veterans are now deceased.
In the Middle Ages
, poor hygiene was partly responsible for the spreading of bubonic plague.
The McCarthy Era
inspired Arthur Miller to write The Crucible .
Roman Britain
is the setting for the Minimus comic books.
Middle school students often enjoy studying the social changes that took place in the Roaring Twenties
.
However, centuries—and the numbers before them—are not capitalized. See the examples below for an illustration of this rule:
In the fifteenth
and sixteenth centuries
, England blossomed into an empire.
In the eighteen hundreds
, the world saw great technological advancement.
