Valentinianism flourished after the middle of the 2nd century AD. This movement was named after its founder Valentinus (c. 100 – 180 AD). The school is also known to have been extremely popular: several varieties of their central myth are known, and we know of “reports from outsiders from which the intellectual liveliness of the group is evident.” It is known that Valentinus’ students elaborated on his teachings and materials (though the exact extent of their changes remains unknown), for example, in the version of the Valentinian myth brought to us through Ptolemy.
Valentinianism might be described as the most elaborate and philosophically “dense” form of the Syrian-Egyptian schools of Gnosticism, though it should be acknowledged that this in no way debarred other schools from attracting followers. Basilides’ own school was popular also, and survived in Egypt until the 4th century.
Simone Petrement, in A Separate God, in arguing for a Christian origin of Gnosticism, places Valentinus after Basilides, but before the Sethians. It is her assertion that Valentinus represented a moderation of the anti-Judaism of the earlier Hellenized teachers; the demiurge, widely regarded to be a mythological depiction of the Old Testament God of the Hebrews, is depicted as more ignorant than evil.
An alternate heritage is offered by Kurt Rudolph in his book Gnosis: The Nature & Structure of Gnosticism (Koehler and Amelang, Leipzig, 1977), to explain the lineage of Persian Gnostic schools. The decline of Manicheism 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 (where Augustine was a member of the school from 373-382); from Syria it progressed still farther, into Palestine, Asia Minor and Armenia. There is evidence for Manicheans in Rome and Dalmatia in the 4th century, and also in Gaul and Spain. 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, given that 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.