Gnosticism (from Ancient Greek: γνωστικός gnostikos , "having knowledge", from γνῶσις gnōsis , knowledge) is a modern name for a variety of ancient religious ideas and systems, originating in Jewish milieus in the first and second century AD. Based on their readings of the Torah and other Biblical writings, these systems believed that the material world is created by an emanation of the highest God, trapping the Divine spark within the human body. This Divine spark could be liberated by gnosis of this Divine spark.
The Gnostic ideas and systems flourished in the Mediterranean world in the second century AD, in conjunction with and influenced by the early Christian movements and Middle Platonism. After the Second Century, a decline set in, but Gnosticism persisted throughout the centuries as an undercurrent of western culture, remanifesting with the Renaissance as Western esotericism, taking prominence with modern spirituality. In the Persian Empire, Gnosticism spread as far as China with Manicheism, while Mandaeism is still alive in Iraq.
A major question in scholarly research is the qualification of Gnosticism, based on the study of its texts, as either an interreligious phenomenon or as an independent religion.
Gnosis refers to knowledge based on personal experience or perception. In a religious context, gnosis is mystical or esoteric knowledge based on direct participation with the divine. In most Gnostic systems, the sufficient cause of salvation is this "knowledge of" ("acquaintance with") the divine. It is an inward "knowing," comparable to that encouraged by Plotinus ( neoplatonism), and differs from Christian proto-orthodox views.
The usual meaning of gnostikos in Classical Greek texts is "learned" or "intellectual", such as used by Plato in the comparison of "practical" ( praktikos ) and "intellectual" ( gnostikos ). Plato's use of "learned" is fairly typical of Classical texts.
By the Hellenistic period, it began to also be associated with Greco-Roman mysteries, becoming synonymous with the Greek term musterion . The adjective is not used in the New Testament, but Clement of Alexandria speaks of the "learned" ( gnostikos ) Christian in complimentary terms. The use of gnostikos in relation to heresy originates with interpreters of Irenaeus. Some scholars consider that Irenaeus sometimes uses gnostikos to simply mean "intellectual", whereas his mention of "the intellectual sect" is a specific designation.
The term "Gnosticism" does not appear in ancient sources, and was first coined in the 17th Century by Henry More in a commentary on the seven letters of the Book of Revelation, where More used the term "Gnosticisme" to describe the heresy in Thyatira. The term Gnosticism was derived from the use of the Greek adjective gnostikos (Greek γνωστικός, "learned," "intellectual") by St. Irenaeus (c. 185 AD) to describe the school of Valentinus as he legomene gnostike haeresis "the heresy called Learned (gnostic)." 
The earliest origins of Gnosticism are obscure and still disputed. The Christian groups called Gnostics a branch of Christianity, but according to the modern scholars the theology's origin is closely related to Jewish sectarian milieus and early Christian sects. Gnostics seem to have originated in Alexandria and coexisted with the early Christians until the 4th Century AD. Because there was as yet no fixed church authority, syncretism with pre-existing belief systems as well as new religions was often embraced.
Some scholars prefer to speak of "gnosis" when referring to First Century ideas that later developed into gnosticism, and to reserve the term "gnosticism" for the synthesis of these ideas into a coherent movement in the Second Century. No gnostic texts have been discovered that pre-date Christianity, and "pre-Christian Gnosticism as such is hardly attested in a way to settle the debate once and for all."
Contemporary scholarship largely agrees that Gnosticism has Jewish or Judeo-Christian origins, originating in the late First Century AD in nonrabbinical Jewish sects and early Christian sects.
Many heads of gnostic schools were identified as Jewish Christians by Church Fathers, and Hebrew words and names of God were applied in some gnostic systems.  The cosmogonic speculations among Christian Gnostics had partial origins in Ma`aseh Bereshit and Ma`aseh Merkabah. This theses is most notably put forward by Gershom Scholem (1897–1982) and Gilles Quispel (1916-2006). Scholem detected Jewish gnosis in the imagery of the merkavah, which can also be found in "Christian" Gnostic documents, for example Paul's ascension to the third heaven. Quispel sees Gnosticism as an independent Jewish development, tracing its origins to Alexandrian Jews, to which group Valentinus was also connected. According to Robert M. Grant, Gnosticism developed out of "the remains of apocalyptic eschatological expectations after the fall of Jerusalem", which shattered the hopes of the coming of God's kingdom on earth and led to a rejection of the world. Gnosticism united material from the "outer fringes of Judaism" such as the Essenes and the Diaspora Judaism of the Aramaic Syro-Mesopotamian world.
Many of the Nag Hammadi texts make reference to Judaism, in some cases with a violent rejection of the Jewish God. Gershom Scholem once described Gnosticism as "the Greatest case of metaphysical anti-Semitism". Professor Steven Bayme said gnosticism would be better characterized as anti-Judaism.  Recent research into the origins of Gnosticism shows a strong Jewish influence, particularly from Hekhalot literature. 
Within early Christianity, the teachings of Paul and John may have been a starting point for Gnostic ideas, with a growing emphasis on the opposition between flesh and spirit, the value of charisma, and the disqualification of the Jewish law. The mortal body belonged to the world of the archons , and only the spirit or soul could be saved. The term gnostikos may have acquired a deeper significance here.
Alexandria was of central importance for the birth of Gnosticism. The Christian ecclesia was of Jewish–Christian origin, but also attracted Greek members, and various strand of thought were available, such as "Judaic apocalypticism, speculation on divine wisdom, Greek philosophy, and Hellenistic mystery religions."
Regarding the angel Christology of some early Christians, Darrell Hannah notes:
[Some] early Christians understood the pre-incarnate Christ, ontologically, as an angel. This "true" angel Christology took many forms and may have appeared as early as the late First Century, if indeed this is the view opposed in the early chapters of the Epistle to the Hebrews. The Elchasaites, or at least Christians influenced by them, paired the male Christ with the female Holy Spirit, envisioning both as two gigantic angels. Some Valentinian Gnostics supposed that Christ took on an angelic nature that he might be the Saviour of angels. The author of the Testament of Solomon held Christ to be a particularly effective "thwarting" angel in the exorcism of demons. The author of De Centesima and Epiphanius’ "Ebionites" held Christ to have been the highest and most important of the first created archangels, a view similar in many respects to Hermas’ equation of Christ with Michael. Finally, a possible exegetical tradition behind the Ascension of Isaiah and attested by Origen's Hebrew master, may witness to yet another angel Christology, as well as an angel Pneumatology. 
[The Lord Christ is commissioned by the Father] And I heard the voice of the Most High, the father of my LORD as he said to my LORD Christ who will be called Jesus, ‘Go out and descend through all the heavens... 
The Shepherd of Hermas is a Christian literary work considered as canonical scripture by some of the early Church fathers such as Irenaeus. Jesus is identified with angel Christology in parable 5, when the author mentions a Son of God, as a virtuous man filled with a Holy "pre-existent spirit". 
In the 1880s Gnostic connections with neo-Platonism were proposed. Ugo Bianchi, who organised the Congress of Medina of 1966 on the origins of Gnosticism, also argued for Orphic and Platonic origins. Gnostics borrowed significant ideas and terms from Platonism, using Greek philosophical concepts throughout their text, including such concepts as hypostasis (reality, existence), ousia (essence, substance, being), and demiurge (creator God). Both Sethian Gnostics and Valentinian Gnostics seem to have been influenced by Plato, Middle Platonism, and Neo-Pythagoreanism academies or schools of thought. Both schools attempted "an effort towards conciliation, even affiliation" with late antique philosophy, and were rebuffed by some Neoplatonists, including Plotinus.
Persian origins or influences
Early research into the origins of Gnosticism proposed Persian origins or influences, spreading to Europe and incorporating Jewish elements. According to Wilhelm Bousset (1865–1920), Gnosticism was a form of Iranian and Mesopotamian syncretism, and Richard August Reitzenstein (1861–1931) most famously situated the origins of Gnosticism in Persia.
Carsten Colpe (b. 1929) has analyzed and criticised the Iranian hypothesis of Reitzenstein, showing that many of his hypotheses are untenable. Nevertheless, Geo Widengren (1907–1996) argued for the origin of (Mandaean) Gnosticism in Mazdean (Zoroastrianism) Zurvanism, in conjunction with ideas from the Aramaic Mesopotamian world.
In 1966, at the Congress of Median, Buddhologist Edward Conze noted phenomenological commonalities between Mahayana Buddhism and Gnosticism, in his paper Buddhism and Gnosis , following an early suggestion put forward by Isaac Jacob Schmidt. The influence of Buddhism in any sense on either the gnostikos Valentinus (c. 170) or the Nag Hammadi texts (3rd Century) is not supported by modern scholarship, although Elaine Pagels (1979) called it a "possibility". 
The Syrian–Egyptian traditions postulate a remote, supreme Godhead, the Monad. From this highest divinity emanate lower divine beings, known as Aeons. The Demiurge, one of those Aeons, creates the physical world. Divine elements "fall" into the material realm, and are locked within human beings. This divine element returns to the divine realm when Gnosis, esoteric or intuitive knowledge of the divine element within, is obtained.
Dualism and monism
Gnostic systems postulate a dualism between God and the world, varying from the "radical dualist" systems of Manichaeism to the "mitigated dualism" of classic gnostic movements. Radical dualism, or absolute dualism, posits two co-equal divine forces, while in mitigated dualism one of the two principles is in some way inferior to the other. In qualified monism the second entity may be divine or semi-divine. Valentinian Gnosticism is a form of monism, expressed in terms previously used in a dualistic manner.
Moral and ritual practice
Gnostics tended toward asceticism, especially in their sexual and dietary practice. In other areas of morality, Gnostics were less rigorously ascetic, and took a more moderate approach to correct behaviour. In normative early Christianity the Church administered and prescribed the correct behaviour for Christians, while in Gnosticism it was the internalised motivation that was important. Ritualistic behaviour was not important unless it was based on a personal, internal motivation. Ptolemy's Epistle to Flora describes a general asceticism, based on the moral inclination of the individual.
In many Gnostic systems, God is known as the Monad , the One. God is the high source of the pleroma, the region of light. The various emanations of God are called æons. According to Hippolytus, this view was inspired by the Pythagoreans, who called the first thing that came into existence the Monad , which begat the dyad, which begat the numbers, which begat the point, begetting lines, etc.
The Sethian cosmogony as most famously contained in the Apocryphon ("Secret book") of John describes an unknown God, very similar to the orthodox apophatic theology, but different from the orthodox teachings that this God is the creator of heaven and earth. Orthodox theologians often attempt to define God through a series of explicit positive statements: he is omniscient, omnipotent, and truly benevolent. The Sethian hidden transcendent God is, by contrast, defined through negative theology: he is immovable, invisible, intangible, ineffable; commonly, "he" is seen as being hermaphroditic, a potent symbol for being, as it were, "all-containing". In the Apocryphon of John, this god is good in that it bestows goodness. After the apophatic statements, the process of the Divine in action are used to describe the effect of such a god.
Pleroma (Greek πληρωμα, "fullness") refers to the totality of God's powers. The heavenly pleroma is the center of divine life, a region of light "above" (the term is not to be understood spatially) our world, occupied by spiritual beings such as aeons (eternal beings) and sometimes archons. Jesus is interpreted as an intermediary aeon who was sent from the pleroma, with whose aid humanity can recover the lost knowledge of the divine origins of humanity. The term is thus a central element of Gnostic cosmology.
Pleroma is also used in the general Greek language, and is used by the Greek Orthodox church in this general form, since the word appears in the book of Colossians. Proponents of the view that Paul was actually a gnostic, such as Elaine Pagels, view the reference in Colossians as a term that has to be interpreted in a gnostic sense.
The Supreme Light or Consciousness descends through a series of stages, gradations, worlds, or hypostases, becoming progressively more material and embodied. In time it will turn around to return to the One (epistrophe), retracing its steps through spiritual knowledge and contemplation.
In many Gnostic systems, the aeons are the various emanations of the superior God or Monad. From this first being, also an æon, a series of different emanations occur, beginning in certain Gnostic texts with the hermaphroditic Barbelo,    from which successive pairs of aeons emanate, often in male–female pairings called syzygies .  The numbers of these pairings varied from text to text, though some identify their number as being thirty. The aeons as a totality constitute the pleroma , the "region of light". The lowest regions of the pleroma are closest to the darkness; that is, the physical world.
Two of the most commonly paired æons were Christ and Sophia (Greek: "Wisdom"); the latter refers to Christ as her "consort" in A Valentinian Exposition . 
In Gnostic tradition, the term Sophia (Σoφíα, Greek for "wisdom") refers to the final and lowest emanation of God. In most if not all versions of the gnostic myth, Sophia births the demiurge, who in turn brings about the creation of materiality. The positive or negative depiction of materiality thus resides a great deal on mythic depictions of Sophia's actions. She is occasionally referred to by the Hebrew equivalent of Achamoth (this is a feature of Ptolemy's version of the Valentinian gnostic myth). Jewish Gnosticism with a focus on Sophia was active by 90 CE.
Sophia , emanating without her partner, resulted in the production of the Demiurge (Greek: lit. "public builder"),  who is also referred to as Yaldabaoth and variations thereof in some Gnostic texts.  This creature is concealed outside the pleroma;  in isolation, and thinking itself alone, it creates materiality and a host of co-actors, referred to as archons. The demiurge is responsible for the creation of mankind; trapping elements of the pleroma stolen from Sophia inside human bodies.   In response, the Godhead emanates two savior aeons, Christ and the Holy Spirit ; Christ then embodies itself in the form of Jesus, in order to be able to teach man how to achieve gnosis, by which they may return to the pleroma. 
The term demiurge derives from the Latinized form of the Greek term dēmiourgos , δημιουργός, literally "public or skilled worker". This figure is also called "Ialdabaoth",  Samael ( Aramaic: sæmʻa-ʼel , "blind god"), or "Saklas" ( Syriac: sækla , "the foolish one"), who is sometimes ignorant of the superior god, and sometimes opposed to it; thus in the latter case he is correspondingly malevolent. Other names or identifications are Ahriman, El, Satan, and Yahweh.
The demiurge creates the physical universe and the physical aspect of humanity.  The demiurge typically creates a group of co-actors named archons who preside over the material realm and, in some cases, present obstacles to the soul seeking ascent from it.  The inferiority of the demiurge's creation may be compared to the technical inferiority of a work of art, painting, sculpture, etc. to the thing the art represents. In other cases it takes on a more ascetic tendency to view material existence negatively, which then becomes more extreme when materiality, including the human body, is perceived as evil and constrictive, a deliberate prison for its inhabitants.
Moral judgements of the demiurge vary from group to group within the broad category of Gnosticism, viewing materiality as being inherently evil, or as merely flawed and as good as its passive constituent matter allows. 
In late antiquity some variants of Gnosticism used the term archon to refer to several servants of the demiurge.  In this context they may be seen as having the roles of the angels and demons of the Old Testament.
According to Origen's Contra Celsum , a sect called the Ophites posited the existence of seven archons, beginning with Iadabaoth or Ialdabaoth, who created the six that follow: Iao, Sabaoth, Adonaios, Elaios, Astaphanos, and Horaios.  Similarly to the Mithraic Kronos and Vedic Narasimha, a form of Vishnu, Ialdabaoth had a head of a lion.   
Other Gnostic concepts are:
- sarkic – earthly, hidebound, ignorant, uninitiated. The lowest level of human thought; the fleshly, instinctive level of thinking.
- hylic – lowest order of the three types of human. Unable to be saved since their thinking is entirely material, incapable of understanding the gnosis.
- psychic – "soulful", partially initiated. Matter-dwelling spirits
- pneumatic – "spiritual", fully initiated, immaterial souls escaping the doom of the material world via gnosis.
- kenoma – the visible or manifest cosmos, "lower" than the pleroma
- charisma – gift, or energy, bestowed by pneumatics through oral teaching and personal encounters
- logos – the divine ordering principle of the cosmos; personified as Christ. See also Odic force.
- hypostasis – literally "that which stands beneath" the inner reality, emanation (appearance) of God, known to psychics
- ousia – essence of God, known to pneumatics. Specific individual things or being.
Jesus as Gnostic saviour
Jesus is identified by some Gnostics as an embodiment of the supreme being who became incarnate to bring gnōsis to the earth,   while others adamantly denied that the supreme being came in the flesh, claiming Jesus to be merely a human who attained divinity through gnosis and taught his disciples to do the same. Among the Mandaeans, Jesus was considered a mšiha kdaba or " false messiah " who perverted the teachings entrusted to him by John the Baptist. Still other traditions identify Mani and Seth – third son of Adam and Eve – as salvific figures.
Three periods can be discerned in the development of Gnosticism:
- Late First Century and early Second Century: development of Gnostic ideas, contemporaneous with the writing of the New Testament;
- mid-Second Century to early Third Century: high point of the classical Gnostic teachers and their systems, "who claimed that their systems represented the inner truth revealed by Jesus";
- end of Second Century to Fourth Century: reaction by the proto-orthodox church and condemnation as heresy, and subsequent decline.
During the first period, four types of tradition developed:
- Genesis was reinterpreted in Jewish milieus, viewing Jahweh as a jealous God who enslaved people; freedom was to be obtained from this jealous God;
- A wisdom tradition developed, in which Jesus' sayings were interpreted as pointers to an esoteric wisdom, in which the soul could be divinized through identification with wisdom. Some of Jesus' sayings may have been incorporated into the gospels to put a limit on this development. The conflicts described in 1 Corinthians may have been inspired by a clash between this wisdom tradition and Paul's gospel of crucifixion and arising;
- A soteriology developed from popular forms of Platonism in which the soul ascended to union with the Divine;
- A mythical story developed about the descent of a heavenly creature to reveal the Divine world as the true home of human beings. Jewish Christianity saw the Messiah, or Christ, as "an eternal aspect of God's hidden nature, his "spirit" and "truth," who revealed himself throughout sacred history."
The movement spread in areas controlled by the Roman Empire and Arian Goths, and the Persian Empire. It continued to develop in the Mediterranean and Middle East before and during the 2nd and 3rd centuries, but decline also set in during the Third Century CE, due to a growing aversion from the Catholic Church, and the economic and cultural deterioration of the Roman Empire. Conversion to Islam, and the Albigensian Crusade (1209–1229), greatly reduced the remaining number of Gnostics throughout the Middle Ages, though a few Mandaean communities still exist. Gnostic and pseudo-gnostic ideas became influential in some of the philosophies of various esoteric mystical movements of the 19th and 20th centuries in Europe and North America, including some that explicitly identify themselves as revivals or even continuations of earlier gnostic groups.
Relation with early Christianity
Dillon notes that Gnosticism raises questions about the development of early Christianity.
Orthodoxy and heresy
The Christian heresiologists, most notably Irenaeus, regarded Gnosticism as a Christian heresy. Modern scholarship notes that early Christianity was very diverse, and Christian orthodoxy only settled in the 4th Century, when the Roman Empire declined and Gnosticism lost its influence. Gnostics and proto-orthodox Christians shared some terminology. Initially, they were hard to distinguish from each other.
According to Walter Bauer, "heresies" may well have been the original form of Christianity in many regions. This theme was further developed by Elaine Pagels, who argues that "the proto-orthodox church found itself in debates with gnostic Christians that helped them to stabilize their own beliefs." According to Gilles Quispel, Catholicism arose in response to Gnosticism, establishing safeguards in the form of the monarchic episcopate, the creed, and the canon of holy books.
The Gnostic movements may contain information about the historical Jesus, since some texts preserve sayings which show similarities with canonical sayings. Especially the Gospel of Thomas has a significant amount of parallel sayings. Yet, a striking difference is that the canonical sayings center on the coming endtime, while the Thomas-sayings center on a kingdom of heaven that is already here, and not a future event. According to Koester, this is because the Thomas-sayings are older, implying that in the earliest forms of Christianity Jesus was regarded as a wisdom-teacher. An alternative hypothesis states that the Thomas authors wrote in the Second Century CE, changing existing sayings and eliminating the apocalyptic concerns. According to April DeConinck, such a change occurred when the endtime did not come, and the Thomasine tradition turned toward a "new theology of mysticism" and a "theological commitment to a fully-present kingdom of heaven here and now, where their church had attained Adam and Eve's divine status before the Fall."
The prologue of the Gospel of John describes the incarnated Logos, the light that came to earth, in the person of Jesus. The Apocryphon of John contains a scheme of three descendants from the heavenly realm, the third one being Jesus, just as in the Gospel of John. The similarities probably point to a relationship between gnostic ideas and the Johannine community. According to Raymond Brown, the Gospel of John shows "the development of certain gnostic ideas, especially Christ as heavenly revealer, the emphasis on light versus darkness, and anti-Jewish animus." The Johannine material reveals debates about the redeemer myth. The Johannine letters show that there were different interpretations of the gospel story, and the Johannine images may have contributed to Second Century Gnostic ideas about Jesus as a redeemer who descended from heaven. According to DeConinck, the Gospel of John shows a "transitional system from early Christianity to gnostic beliefs in a God who transcends our world." According to DeConinck, the John shows a beginning bifurcation between Jesus' "Father in Heaven," and the Jews "Father of the Devil," which may have developed into the gnostic idea of the Monad and the Demiurge.
Paul and Gnosticism
Tertullian calls Paul "the apostle of the heretics", because Paul's writings were attractive to gnostics, and interpreted in a gnostic way, while Jewish Christians found him to stray from the Jewish roots of Christianity. Paul wrote to the Corinthian church members as "having knowledge" ( Greek: τον εχοντα γνωσιν , ton echonta gnosin ).  Dunn claims that in some cases, Paul affirmed views that were closer to gnosticism than to proto-orthodox Christianity.
According to Clement of Alexandria, the disciples of Valentinus said that Valentinus was a student of a certain Theudas, who was a student of Paul, and Elaine Pagels notes that Paul's epistles were interpreted by Valentinus in a gnostic way, and Paul could be considered a proto- gnostic as well as a proto- Catholic. Many Nag Hammadi texts, including, for example, the Prayer of Paul and the Coptic Apocalypse of Paul , consider Paul to be "the great apostle". The fact that he claimed to have received his gospel directly by revelation from God appealed to the gnostics, who claimed gnosis from the risen Christ. The Naasenes, Cainites, and Valentinians referred to Paul's epistles. Authors such as Timothy Freke and Peter Gandy have expanded upon this idea of Paul as a gnostic teacher; nevertheless, Paul does not claim to be a gnostic, and his revelation was different from the gnostic revelations.
Syrian-Egyptian Gnosticism includes Sethianism, Valentinianism, Basilideans, Thomasine traditions, and Serpent Gnostics, as well as a number of other minor groups and writers. Hermeticism is also a western Gnostic tradition, though it differs in some respects from these other groups.  The Syrian–Egyptian school derives much of its outlook from Platonist influences. It depicts creation in a series of emanations from a primal monadic source, finally resulting in the creation of the material universe. These schools tend to view evil in terms of matter that is markedly inferior to goodness and lacking spiritual insight and goodness rather than as an equal force.
Many of these movements used texts related to Christianity, with some identifying themselves as specifically Christian, though quite different from the Orthodox or Roman Catholic forms. Jesus and several of his apostles, such as Thomas the Apostle, claimed as the founder of the Thomasine form of Gnosticism, figure in many Gnostic texts. Mary Magdalene is respected as a Gnostic leader, and is considered superior to the twelve apostles by some gnostic texts, such as the Gospel of Mary. John the Evangelist is claimed as a Gnostic by some Gnostic interpreters, as is even St Paul. Most of the literature from this category is known to us through the Nag Hammadi Library.
Sethianism was one of the main currents of Gnosticism during the 2nd to 3rd centuries, and the prototype of Gnosticism as condemned by Irenaeus. Sethianism attributed its gnosis to Seth, third son of Adam and Eve and Norea , wife of Noah, who also plays a role in Mandeanism and Manicheanism. Their main text is the Apocryhon of John , which does not contain Christian elements, and is an amalgam of two earlier myths. Earlier texts such as Apocalypse of Adam show signs of being pre-Christian and focus on the Seth, third son of Adam and Eve. Later Sethian texts continue to interact with Platonism. Sethian texts such as Zostrianos and Allogenes draw on the imagery of older Sethian texts, but utilize "a large fund of philosophical conceptuality derived from contemporary Platonism, (that is, late middle Platonism) with no traces of Christian content."
According to John D. Turner, German and American scholarship views Sethianism as "a distinctly inner-Jewish, albeit syncretistic and heterodox, phenomenon", while British and French scholarship tends to see Sethianism as "a form of heterodox Christian speculation". Roelof van den Broek notes that "Sethianism" may never have been a separate religious movement, and that the term refers rather to a set of mythological themes which occur in various texts.
According to Smith, Sethianism may have begun as a pre-Christian tradition, possibly a syncretic cult that incorporated elements of Christianity and Platonism as it grew. According to Temporini, Vogt, and Haase, early Sethians may be identical to or related to the Nazarenes (sect), the Ophites, or the sectarian group called heretics by Philo.
According to Turner, Sethianism was influenced by Christianity and Middle Platonism, and originated in the Second Century CE as a fusion of a Jewish baptizing group of possibly priestly lineage, the so-called Barbeloites , named after Barbelo, the first emanation of the Highest God, and a group of Bibilical exegetes, the Sethites , the "seed of Seth ". At the end of the Second Century, Sethianism grew apart from the developing Christian orthodoxy, which rejected the docetian view of the Sethians on Christ. In the early Third Century, Sethianism was fully rejected by Christian heresiologists, as Sethianism shifted toward the contemplative practices of Platonism while losing interest in their own origins. In the late Third Century, Sethianism was attacked by neo-Platonists like Plotinus, and Sethianism became alienated from Platonism. In the early- to mid-Fourth Century, Sethianism fragmented into various sectarian Gnostic groups such as the Archontics, Audians, Borborites, and Phibionites, and perhaps Stratiotici, and Secundians). Some of these groups existed into the Middle Ages.
Samaritan Baptist sects
According to Magris, Samaritan Baptist sects were an offshoot of John the Baptist. One offshoot was in turn headed by Dositheus, Simon Magus, and Menander. It was in this milieu that the idea emerged that the world was created by ignorant angels. Their baptismal ritual removed the consequences of sin, and led to a regeneration by which natural death, which was caused by these angels, was overcome. The Samaritan leaders were viewed as "the embodiment of God's power, spirit, or wisdom, and as the redeemer and revealer of 'true knowledge'".
The Simonians were centered on Simon Magus, the magician baptised by Philip and rebuked by Peter in Acts 8, who became in early Christianity the archetypal false teacher. The ascription by Justin Martyr, Irenaeus, and others of a connection between schools in their time and the individual in Acts 8 may be as legendary as the stories attached to him in various apocryphal books. Justin Martyr identifies Menander of Antioch as Simon Magus' pupil. According to Hippolytus, Simonianism is an earlier form of the Valentinian doctrine.
The Basilidians or Basilideans were founded by Basilides of Alexandria in the Second Century. Basilides claimed to have been taught his doctrines by Glaucus, a disciple of St. Peter, but could also have been a pupil of Menander. Basilidianism survived until the end of the 4th Century as Epiphanius knew of Basilidians living in the Nile Delta. It was, however, almost exclusively limited to Egypt, though according to Sulpicius Severus it seems to have found an entrance into Spain through a certain Mark from Memphis. St. Jerome states that the Priscillianists were infected with it.
Valentinianism was named after its founder Valentinus (c. 100 – 180 AD), who was a candidate for bishop of Rome but started his own group when another was chosen. Valentinianism flourished after the middle of the 2nd Century AD. The school was popular, spreading to Northwest Africa and Egypt, and through to Asia Minor and Syria in the east, and Valentinus is specifically named as gnostikos by Irenaeus. It was an intellectually vibrant tradition, with an elaborate and philosophically "dense" form of Gnosticism. Valentinus' students elaborated on his teachings and materials, and several varieties of their central myth are known.
Valentinian Gnosticism may have been monistic rather than dualistic. In the Valentinian myths, the creation of a flawed materiality is not due to any moral failing on the part of the Demiurge, but due to the fact that he is less perfect than the superior entities from which he emanated.  Valentinians treat physical reality with less contempt than other Gnostic groups, and conceive of materiality not as a separate substance from the divine, but as attributable to an error of perception which becomes symbolized mythopoetically as the act of material creation. 
The followers of Valentinius attempted to systematically decode the Epistles, claiming that most Christians made the mistake of reading the Epistles literally rather than allegorically. Valentinians understood the conflict between Jews and Gentiles in Romans to be a coded reference to the differences between Psychics (people who are partly spiritual but have not yet achieved separation from carnality) and Pneumatics (totally spiritual people). The Valentinians argued that such codes were intrinsic in gnosticism, secrecy being important to ensuring proper progression to true inner understanding.
According to Bentley Layton "Classical Gnosticism" and "The School of Thomas" antedated and influenced the development of Valentinus, whom Layton called "the great [Gnostic] reformer" and "the focal point" of Gnostic development. While in Alexandria, where he was born, Valentinus probably would have had contact with the Gnostic teacher Basilides, and may have been influenced by him. Simone Petrement, while arguing for a Christian origin of Gnosticism, places Valentinus after Basilides, but before the Sethians. According to Petrement, Valentinus represented a moderation of the anti-Judaism of the earlier Hellenized teachers; the demiurge, widely regarded as a mythological depiction of the Old Testament God of the Hebrews, is depicted as more ignorant than evil.
The Thomasine Traditions refers to a group of texts which are attributed to the apostle Thomas.  Karen L. King notes that "Thomasine Gnosticism" as a separate category is being criticised, and may "not stand the test of scholarly scrutiny".
Marcion was a Church leader from Sinope (present-day Turkey), who preached in Rome around 150 CE, but was expelled and started his own congregation, which spread throughout the Mediterranean. He rejected the Old Testament, and followed a limited Christian canon, which included only a redacted version of Luke, and ten edited letters of Paul. Some scholars do not consider him to be a gnostic,  but his teachings clearly resemble some Gnostic teachings. He preached a radical difference between the God of the Old Testament, the Demiurge, and the highest God, who had sent Jesus to the earth to free mankind from the tyranny of the Jewish Law. Like the Gnostics, Marcion argued that Jesus was essentially a divine spirit appearing to men in the shape of a human form, and not someone in a true physical body.  Marcion held that the heavenly Father (the father of Jesus Christ) was an utterly alien god; he had no part in making the world, nor any connection with it. 
Other Gnostic groups
- Serpent Gnostics. The Naassenes, Ophites and the Serpentarians gave prominence to snake symbolism, and snake handling played a role in their ceremonies.
- Cerinthus (c. 100 AD), the founder of a heretical school with gnostic elements. Like a Gnostic, Cerinthus depicted Christ as a heavenly spirit separate from the man Jesus, and he cited the demiurge as creating the material world. Unlike the Gnostics, Cerinthus taught Christians to observe the Jewish law; his demiurge was holy, not lowly; and he taught the Second Coming. His gnosis was a secret teaching attributed to an apostle. Some scholars believe that the First Epistle of John was written as a response to Cerinthus.
- The Cainites are so-named since Hippolytus of Rome claims that they worshiped Cain, as well as Esau, Korah, and the Sodomites. There is little evidence concerning the nature of this group. Hippolytus claims that they believed that indulgence in sin was the key to salvation because since the body is evil, one must defile it through immoral activity (see libertinism). The name Cainite is used as the name of a religious movement, and not in the usual Biblical sense of people descended from Cain.
- The Carpocratians, a libertine sect following only the Gospel according to the Hebrews
- The Borborites, a libertine Gnostic sect, said to be descended from the Nicolaitans
The Persian Schools, which appeared in the western Persian province of Babylonia (in particular, within the Sassanid province of Asuristan), and whose writings were originally produced in the Aramaic dialects spoken in Babylonia at the time, are representative of what is believed to be among the oldest of the Gnostic thought forms. These movements are considered by most to be religions in their own right, and are not emanations from Christianity or Judaism.
Manichaeism was founded by the Prophet Mani (216–276 AD). Mani's father was a member of the Jewish-Christian sect of the Elcesaites, a subgroup of the Gnostic Ebionites. At ages 12 and 24, Mani had visionary experiences of a "heavenly twin" of his, calling him to leave his father's sect and preach the true message of Christ. In 240–41, Mani travelled to the Indo-Greek Kingdom of the Sakhas in modern-day Afghanistan, where he studied Hinduism and its various extant philosophies. Returning in 242, he joined the court of Shapur I, to whom he dedicated his only work written in Persian, known as the Shabuhragan . The original writings were written in Syriac Aramaic, in a unique Manichaean script.
Manichaeism conceives of two coexistent realms of light and darkness that become embroiled in conflict. Certain elements of the light became entrapped within darkness, and the purpose of material creation is to engage in the slow process of extraction of these individual elements. In the end the kingdom of light will prevail over darkness. Manicheanism inherits this dualistic mythology from Zurvanist Zoroastrianism, in which the eternal spirit Ahura Mazda is opposed by his antithesis, Angra Mainyu. This dualistic teaching embodied an elaborate cosmological myth that included the defeat of a primal man by the powers of darkness that devoured and imprisoned the particles of light. 
According to Kurt Rudolph, the decline of Manichaeism that occurred in Persia in the 5th Century was too late to prevent the spread of the movement into the east and the west. In the west, the teachings of the school moved into Syria, Northern Arabia, Egypt and North Africa. There is evidence for Manicheans in Rome and Dalmatia in the 4th Century, and also in Gaul and Spain. From Syria it progressed still farther, into Palestine, Asia Minor and Armenia. The influence of Manicheanism was attacked by imperial elects and polemical writings, but the religion remained prevalent until the 6th Century, and still exerted influence in the emergence of the Paulicians, Bogomils and Cathari in the Middle Ages, until it was ultimately stamped out by the Catholic Church.
In the east, Rudolph relates, Manicheanism was able to bloom, because the religious monopoly position previously held by Christianity and Zoroastrianism had been broken by nascent Islam. In the early years of the Arab conquest, Manicheanism again found followers in Persia (mostly amongst educated circles), but flourished most in Central Asia, to which it had spread through Iran. Here, in 762, Manicheanism became the state religion of the Uyghur Empire.
The Mandaeans are Semites and speak a dialect of Eastern Aramaic known as Mandaic. Their religion has been practised primarily around the lower Karun, Euphrates and Tigris and the rivers that surround the Shatt-al-Arab waterway, part of southern Iraq and Khuzestan Province in Iran. Mandaeanism is still practiced in small numbers, in parts of southern Iraq and the Iranian province of Khuzestan, and there are thought to be between 60,000 and 70,000 Mandaeans worldwide. 
The name of the group derives from the term Mandā d-Heyyi , which roughly means "Knowledge of Life." Although the exact chronological origins of this movement are not known, John the Baptist eventually came to be a key figure in the religion, as an emphasis on baptism is part of their core beliefs. As with Manichaeism, despite certain ties with Christianity, Mandaeans do not believe in Moses, Jesus, or Mohammed. Their beliefs and practices likewise have little overlap with the religions that manifested from those religious figures and the two should not be confused. Significant amounts of original Mandaean Scripture, written in Mandaean Aramaic, survive in the modern era. The primary source text is known as the Genzā Rabbā and has portions identified by some scholars as being copied as early as the 3rd Century AD. There is also the Qolastā, or Canonical Book of Prayer and The Book of John the Baptist (sidra ḏ-iahia).
After its demise in the Mediterranean world, Gnosticism lived on in the periphery of the Byzantine Empire, and resurfaced in the western world. The Paulicians, an Adoptionist group which flourished between 650 and 872 in Armenia and the Eastern Themes of the Byzantine Empire, were accused by orthodox medieval sources of being Gnostic and quasi Manichaean Christian. The Bogomils, emerged in Bulgaria between 927 and 970 and spread throughout Europe. It was as synthesis of Armenian Paulicianism and the Bulgarian Orthodox Church reform movement.
The Cathars (Cathari, Albigenses or Albigensians) were also accused by their enemies of the traits of Gnosticism; though whether or not the Cathari possessed direct historical influence from ancient Gnosticism is disputed. If their critics are reliable the basic conceptions of Gnostic cosmology are to be found in Cathar beliefs (most distinctly in their notion of a lesser, Satanic, creator god), though they did not apparently place any special relevance upon knowledge ( gnosis ) as an effective salvific force.
Influence on Islam
Gnostic thoughts found their way into Islam during the early medieval age. The Quran and Islamic anthropogenic share gnostic ideas and appear especially among the Sufi, Shia and Ismaili traditions. However, according to the Islamic belief in strict Oneness of God, there was no room for a lower deity; such as the demiurge, although some early writings and exegesis mentioned Iblis as the ruler over the lower heavens and earth. Especially in the "Um-al Kitab" Azazel resembles the gnostic demiurge. Like the demiurge, he is endowed with the ability to create his own world and seeks to imprison humans in the material world, but here, his power is limited and depends on the higher God. Like the gnostic conception of human beings imprisoned in matter, Islam acknowledges the human soul is an accomplice of the material world and subject to bodily desires similar to the way archontic spheres envelop the pneuma. The Ruh must therefore gain victory over the lower and material-bound psyche, to overcome his animal nature. A human being captured by his animal desires, mistakenly claims autonomy and independence from the "higher God", thus resembling the lower deity in classical gnostic traditions. The higher God or Monad is identified by Sufis with the God in the Quran.
Gnostic ideas found a Jewish variation in the mystical study of Kabbalah. Many core Gnostic ideas reappear in Kabbalah, where they are used for dramatically reinterpreting earlier Jewish sources according to this new system. The Kabbalists originated in 13th Century Provence, which was at that time also the center of the Gnostic Cathars. While some scholars in the middle of the 20th Century tried to assume an influence between the Cathar "gnostics" and the origins of the Kabbalah, this assumption has proved to be an incorrect generalization not substantiated by any original texts. On the other hand, other scholars, such as Scholem, have postulated that there was originally a "Jewish gnosticism", which influenced the early origins of gnosticism.
Kabbalah does not employ the terminology or labels of non-Jewish Gnosticism, but grounds the same or similar concepts in the language of the Torah (the first five books of the Hebrew Bible).  The 13th Century Zohar ("Splendor"), a foundational text in Kabbalah, is written in the style of a Jewish Aramaic Midrash, clarifying the five books of the Torah with a new Kabbalistic system that uses completely Jewish terms. 
The Mandaens are an ancient Gnostic sect that have survived to this day and are found today in Iraq. Their namesake owes to their following John the Baptist and in that country, they have about five thousand followers. A number of ecclesiastical bodies that think of themselves as Gnostic have set up or re-founded since World War II as well, including the Ecclesia Gnostica, Apostolic Johannite Church, Ecclesia Gnostica Catholica, the Thomasine Church, the Alexandrian Gnostic Church, and the North American College of Gnostic Bishops.
A number of 19th Century thinkers such as Arthur Schopenhauer, Albert Pike and Madame Blavatsky studied Gnostic thought extensively and were influenced by it, and even figures like Herman Melville and W. B. Yeats were more tangentially influenced. Jules Doinel "re-established" a Gnostic church in France in 1890, which altered its form as it passed through various direct successors (Fabre des Essarts as Tau Synésius and Joanny Bricaud as Tau Jean II most notably), and, though small, is still active today.
Early 20th Century thinkers who heavily studied and were influenced by Gnosticism include Carl Jung (who supported Gnosticism), Eric Voegelin (who opposed it), Jorge Luis Borges (who included it in many of his short stories), and Aleister Crowley, with figures such as Hermann Hesse being more moderately influenced. Rene Guenon founded the gnostic review, Le Gnose in 1909, before moving to a more Perennialist position, and founding his Traditionalist School. Gnostic Thelemite organizations, such as Ecclesia Gnostica Catholica and Ordo Templi Orientis, trace themselves to Crowley's thought.
The discovery and translation of the Nag Hammadi library after 1945 has had a huge effect on Gnosticism since World War II. Intellectuals who were heavily influenced by Gnosticism in this period include Lawrence Durrell, Hans Jonas, Philip K. Dick and Harold Bloom, with Albert Camus and Allen Ginsberg being more moderately influenced. Celia Green has written on Gnostic Christianity in relation to her own philosophy.