Question

When did activities occur that demonstrate Americans' belief in Manifest Destiny?

Answer 1

The activities that most demonstrated Americans' belief in Manifest Destiny occurred during the 19th century, while thousands of settlers moved west and displaced thousands of natives. 

Answer 2

The phrase was first employed by John L. O'Sullivan in an article on the annexation of Texas published in the July-August 1845 edition of the United States Magazine and Democratic Review, which he edited. The term manifest destiny originated in the1840s.