history vs Dark Ages

history and Dark Ages both are nouns.

Word	Noun	Adjective	Verb	Adverb
history	Yes	No	No	No
Dark Ages	Yes	No	No	No

history (noun)	Dark Ages (noun)
the discipline that records and interprets past events involving human beings	the period of history between classical antiquity and the Italian Renaissance
all that is remembered of the past as preserved in writing; a body of knowledge
a record or narrative description of past events
the aggregate of past events
the continuum of events occurring in succession leading from the past to the present and even into the future