

GNOSTIC
Gnosticism (origin from Greek Gnosis meaning Knowledge), refers to diverse syncretistic religious movements in antiquity consisting of various belief systems - generally united in the teaching that humans are DIVINE souls trapped in a material world created by an imperfect god, the demiurge. Gnosis is contrasted with a superior Entity. Gnosticism was a dualistic religion.
Most assuradly pagan in origin, most religions practiced today take beliefs from this early religious belief system. Gnostic sects existed for sure earlier than the first century BCE, thus predating the birth of Jesus. The movement spread in areas controlled by the Roman Empire and the Goths, and the Persian Empire. A few isolated communities continue to exist to the present as esoteric mystical movements.
What influenced them? What did and do they believe?
Gnosticism is a concept of spiritual experience which has it's roots in many religious practices and is not restricted to Christianity, although that is how most of us learned of it's existance. Gnosticism is found in the Kabbalah of Judaism, the philosophy of NeoPlatonism, and in modern Iraq where a small sect of peasants called Mandaeans (Knowers) survive today. It is a belief system which considers the 'spiritual' word to be the real world and the material world we now live in to be a product of the negative use of that spirituality. Basically it is Knowledge of the heart rather than some learned theist belief.
For the sake of commonality let us take a look at Christian belief in one perspective, through the eyes of it's Mary. Not much is known of this wonderful lady whether you believe or not. I enjoy thinking of her because first and foremost, she was female in a time when women were minimized and driven to the background, after a battle of epic proportions for the 'one true religion'. Unlike the belief systems that existed before Judaism or Christianity or any Eastern Religion, women were the gods and goddesses. The feminine was the only way to know the gods (Knowledge).

Let's look at the Gospel according to Mary Magdelene
The Gospel of Mary was one of the ancient books found in 1945 near Nag Hammadi, Egypt. It gives us an example of the leadership roles of women in early Christianity. Here Mary is described as an apostle, equal in every way to the twelve apostles. She was a kind of spiritual successor to Christ and the leader of the other apostles. In her gospels she gives clear details of visions through heavenly realms during her meditations.
The Acts of Paul and Thecla speaks of women apostles and saints in early Christianity. The acts of Paul and Thecla is the record of the life and times of Thecla, who as a woman of her time had many supernatural and miraculous evens happen to her. She travelled but also lived in a cave. She was a spiritual leader and teacher who instructed people in the "oracles of god". She was so highly esteemed during her life that a temple was erected and dedicated to her. If you study the four gospels of the new testament you will notice that after Christ is resurrected, those four gospels only mention Christ in one short chapter. Wouldn't logic dictate that after someone rises from the dead, that this would be the main focus and obsession of the writers of those gospels? We can only assume that they had no further knowledge to expand on at that time. Only deep thinkers should contemplate the mystical topic. But we do indeed find writings in the Gospel of Mary and in the Book of Pistis Sophia (meaning Faith and wisdom).
The largest Gospel ever discovered, Pistis Sophia, was brought to London from Egypt in 1772 and was published as a book. The great poet William Blake was greatly influenced by it. A poignant teaching in those gospels was the belief in reincarnation and the preexistance of the soul! The writings were meant to liberate souls from material captivity. Souls were meant to travel from the realm of earth to the realm of heaven by a holy stream of light. Ah....Light, let us think about what that meant. To quote, "Seek, all of you, after the Light, so that the power of your soul that is in you may live. Do not cease seeking day or night until you find the mysteries of the Kingdom of Light, which will purify you, make you into Pure Light and lead you into the Kingdom of Light". Meditate into inner space and know. This is profound!