But an emerging group of teachers and students is appalled by the prospective shift, and in recent days has set out to stop it. Moving all of the pre-1450 A.D. history to another course, they contend, will do little to ensure that that part of the human story—which one AP World teacher in Michigan, Tyler George, described to me as “some of the most rich, diverse content of the entire curriculum”—remains a priority.

Critics have been voicing their concerns via in-person forums and social-media platforms. For example, a student-led Change.org petition calling on Trevor Packer, the head of the AP program, to retract the decision, had as of Wednesday well surpassed its original 5,000-signature goal. The petition emphasizes that the decision “removes HUGE amounts of history”—eras that, while accounting for only40 percent of AP World’s total current course work, comprise some 95 percent of human history since the development of agriculture and set the trajectories of civilizations for thousands of years to come. That history includes the technological advancements and environmental transformation that arose during humans’ migration from Africa to regions around the world; the rise of the Persian empire, the Qin dynasty, Teotihuacan in modern-day Mexico, and the Puebloan People in what today is the southwestern U.S.; and the birth of some of the world’s major religions, including Confucianism, Hinduism, and Christianity.

Dylan Black, the New Jersey high-school student who created the online petition, worries that the change threatens to further entrench in Americans’ minds a Eurocentric worldview. He noted in an email that in his AP World class he learned about indigenous populations throughout the Americas before studying the conquest of those empires by countries like Spain. “Without this previous knowledge of American civilizations,” he said, “it would seem like nobody was there until Europe showed up.”

Such sentiments square with those expressed by numerous educators, many of whom are campaigning to at the very least salvage the curriculum’s third period, which encompasses the nearly nine centuries leading up to 1450 A.D.—a time period during which human networks within and across regions flourished and deepened. This class “is probably the only real chance [high-school students] are going to get to learn the African and American and Asian history before European colonization,” said Amanda DoAmaral, a former AP World History teacher of Brazilian and Jewish descent who, at a recent open forum for teachers in Salt Lake City, got into a testy exchange with Packer about the College Board’s values. “It’s so cool for students to learn [the third period] because it’s the one time in history that Europe wasn’t the big dog—it was in the Dark Ages while the rest of the world was innovating.”