Editing Gnosticism (section)

===Heresiologists===
Prior to the discovery of the Nag Hammadi library in 1945 Gnosticism was known primarily through the works of [[heresiologist]]s, [[Church Fathers]] who opposed those movements. These writings had an antagonistic bias against Gnostic teachings, and were incomplete. Several heresiological writers, such as Hippolytus, made little effort to exactly record the nature of the [[sect]]s they reported on, or transcribe their sacred texts. Reconstructions of incomplete Gnostic texts were attempted in modern times, but research on Gnosticism was coloured by the orthodox views of those heresiologists.

[[Justin Martyr]] ({{Circa|100/114|162/168}}) wrote the ''[[First Apology]]'', addressed to [[Roman emperor]] [[Antoninus Pius]], which criticised [[Simon Magus]], [[Menander (gnostic)|Menander]] and [[Marcion]]. Since then, both Simon and Menander have been considered as 'proto-Gnostic'.{{sfn|Markschies|2003|p=37}} [[Irenaeus]] (died {{Circa|202|lk=no}}) wrote ''[[On the Detection and Overthrow of the So-Called Gnosis|Against Heresies]]'' ({{Circa|180–185|lk=no}}), which identifies [[Simon Magus]] from [[Flavia Neapolis]] in [[Samaria]] as the inceptor of Gnosticism. Irenaeus charted an apparent spread of the teachings of Simon through the ancient "knowers" into the teachings of Valentinus and other contemporaneous Gnostic sects.{{refn|group=note|This understanding of the transmission of Gnostic ideas, despite Irenaeus' certain antagonistic bias, is often utilized today, though it has been criticized.}} [[Hippolytus (writer)|Hippolytus]] (170–235) wrote the ten-volume ''[[Refutatio Omnium Haeresium|Refutation Against all Heresies]]'', of which eight have been found. It also focuses on the connection between pre-Socratic ideas and the false beliefs of early Gnostic leaders. Thirty-three of the groups he reported on are considered Gnostic by modern scholars, including 'the foreigners' and 'the [[Seth]] people'. Hippolytus further presents individual teachers such as Simon, [[Valentinus (Gnostic)|Valentinus]], Secundus, [[Ptolemy (gnostic)|Ptolemy]], [[Heracleon]], [[Marcus (Marcosian)|Marcus]] and [[Colorbasus]]. [[Tertullian]] ({{Circa|155|230|lk=no}}) from [[Carthage]] wrote ''Adversus Valentinianos'' ('Against the Valentinians'), c.{{nbsp}}206, and five books around 207–208 chronicling and refuting the teachings of [[Marcion]].