The prevalent idea that the reverence for the cross is limited to the Christian world is disproved by even the most superficial investigation of its place in religious symbolism. The early Christians used every means possible to conceal the pagan origin of their symbols, doctrines, and rituals. They either destroyed the sacred books of other peoples among whom they settled, or made them inaccessible to students of comparative philosophy, apparently believing that in this way they could stamp out all record of the pre-Christian origin of their doctrines. In some cases the writings of various ancient authors were tampered with, passages of a compromising nature being removed or foreign material interpolated.