Why are phrases like "the High Middle Ages" capitalized while e. g. "the sixth century" is not?
Is there a general rule?
Why are phrases like "the High Middle Ages" capitalized while e. g. "the sixth century" is not?
Is there a general rule?
In its chapter on numbers (and select other sections), the Chicago Manual of Style has these recommendations:
[9.33 Centuries] Particular centuries are spelled out and lowercased.
- the twenty-first century
- the eighth and ninth centuries
- from the ninth to the eleventh century
- the eighteen hundreds (the nineteenth century)
[9.35 Eras] Choice of the era designation depends on tradition, academic discipline, or personal preference. Chicago recommends full capitals and no periods.
[8.72 Traditional period names] Some names of periods are capitalized, either by tradition or to avoid ambiguity.
- the Augustan Age
- the Common Era
- the Counter-Reformation
- the Dark Ages
- the Enlightenment
- the Gay Nineties
- the Gilded Age
- the Grand Siècle
- the High Middle Ages (but the early Middle Ages, the late Middle Ages)
[8.74 Historical events and programs] Names of many major historical events and programs are conventionally capitalized. Others, more recent or known by their generic descriptions, are usually lowercased. If in doubt, do not capitalize.
- the Boston Tea Party
- the Cold War (but a cold war, used generically)
- the Cultural Revolution