Original sentence: It defines the "Hidden Ivy league" as a group of small, private, American colleges and universities that provide Ivy League-level educations, while not historically being thought of as the most prestigious schools in the country ("Hidden")
Edited sentence: It defines the "Hidden Ivy league" as a group of small, private, American colleges and universities that provide Ivy League-level educations, while not often being thought of as the most prestigious schools in the country ("Hidden")