Gnosticism was an extreme transcendental form of religion whose beginnings is not quite known but is usually tied to the Christianity era. Gnostics were "people who knew", and their knowledge at once constituted them as a superior class of beings. They believed salvation would come through knowledge and they were the chosen few that would ascend to God and fuse with him.
Gnosticism was more transcendental than Orthodox Christianity in several ways. First of all, Gnostics believed God was not of this earth; a supernatural being not made of matter. The Orthodox view considered Jesus as completely human. He was the divine Son of God, but human none-the-less. Secondly, Gnostics believed the world to be basically evil. They considered the world several levels below real truth. The Orthodox saw the world as essentially good even though evil lurks within it. The goal of Orthodox Christianity was to rid the world of the evils and turn it into the place that God had intended it to be.
Because of the extreme transcendental thinking of the Gnostics, Orthodox bishops got together in what is known as the Ecumenical Councils to determine what was going to be the standard practices and common beliefs in Christianity. One of the declarations that came about was that Christ was fully human, a cosmological trait, and divine as well. In addition, they developed a collection of written scriptures from which to follow and a priest caste to interpret the scriptures. Gnostics didn't have written scripture and although they had priests of a sort, they all taught what they themselves believed to be true and were not in agreement in their teachings.