Scholar Jae Han describes the ancient Manichaean Christian religion as an outsider in the minds of Roman western Christians because it originated in Persia. Manichaeans considered themselves Christian, but heresiologists called them "Manichaeans." In the same vein, Manichaeans called Catholic Christians "Jews." From a Western perspective, if any religion originated in the East, it can't be truly Christian. It was unnatural for Westerners (Romans) to consider a religion Christian if it originated in the East.