A Texas A&M professor has been told not to teach certain writings from Plato, a staple in introductory philosophy courses, because they may violate the university system’s new rules against “advocate” race or gender ideology, or topics concerning sexual orientation, in core classes.

“Plato has been censored,” said Martin Peterson, who clarified that he was speaking not on the university’s behalf, but as an individual.

Peterson learned the decision Tuesday in an email, which was viewed by the Houston Chronicle. Philosophy department head Kristi Sweet told him that the directive stemmed from the Texas A&M System’s new policy. The email also directed him to remove modules on race and gender ideology or be reassigned to another course.