First Centuries A.D.
Gnostic beliefs existed before Christianity, but grew to prominence through their often controversial association with that faith. Gnosis is a Greek term for "knowledge" employed to describe those who believed that everyone has a divine connection with God and that such knowledge can be revealed to a select few by divine inspiration.
In the second century these ideas were shared by many different belief systems including Valentinianism, Manicheanism, Sethian, and Cainism. Their popularity was such that they greatly influenced and competed with what became orthodox Christianity.
Gnostics (pronounced NOSS-ticks) generally believed that all humans possessed, within themselves, a tiny piece of a larger divine mind or power. It was the imperfect influence of the "dark" material world that prevented humans from making a spiritual connection with the "light" of the divine.
Gnostics regarded Jesus as an enlightened teacher whose message could enable an elite group of humans to find the divine spark within their own inner beings and rediscover the connection and become divine themselves, rising above the imperfection of the material world. The ability to acquire such special knowledge was often associated with self-denial.
Some Gnostics also believed that God, whom the Bible calls the father of Jesus, was not the same Yahweh of the Jewish tradition. Gnostics attributed to Yahweh the creation of the evil, material world that they strived to transcend.
As the orthodox church standardized scriptures and ecclesiastical hierarchy, the Gnostics' widespread beliefs were suppressed and destroyed. This was done so effectively that few texts were known until the 1945 discovery of an ancient library in the Egyptian village of Nag 'Hammadi.
Before the Nag 'Hammadi discovery these ideas were best known from the writings of orthodox Christians, such as second-century St. Irenaeus and church father Origen, who refuted Gnostic beliefs point by point. These anti-Gnostic discourses helped to solidify which scriptures eventually became the traditional Christian canon.
Gnostic writings include many gospels outside of the mainstream Christian canon, such as the Gospel of Mary, the Gospel of Thomas, and now the Gospel of Judas.