What part of speech is the italicized word in the sentence below?

What part of speech is the italicized word in the sentence below?

Four score and seven years ago, our forefathers brought forth UPON this continent a new nation conceived in liberty and dedicated to the proposition that all men are created equal.

8 years ago wow. uwu

UPON is a preposition.

It starts the phrase "upon this continent."

http://www.englishclub.com/vocabulary/prepositions-list.htm

The italicized word "upon" is a preposition in the sentence.

The italicized word in the sentence is a preposition.

To determine the part of speech of a word, it is important to understand its function in the sentence. A preposition is a word that shows a relationship between a noun (or pronoun) and another word in the sentence. In this case, the word "upon" shows the relationship between "brought forth" and "this continent." It indicates the location or position of the action.