Are pronouns considered nouns?
A pronoun can substitute for a noun. They both have many uses, since they can be:
Take a look at this example:
Julius Caesar was a Roman statesman.
Julius Caesar is a proper noun here. However, it can be replaced with a pronoun without changing the meaning of the sentence. The pronoun he can be used:
He was a Roman statesman.
This can also be shown in an example where the noun and pronoun aren't the subject of the sentence:
I read the poem by Maya Angelou.
Maya Angelou is a proper noun and the object of the preposition. It can be replaced with the prepositional pronoun her.
I read the poem by her.