of original sin. Through the act of Christian conversion, individuals can become children of God through adoption. The serpent seed doctrine undermines the basic teachings of Christian conversion by teaching the belief that only individuals who are descended from Adam are the inherent children of God, a belief which classifies them as the only people who do not need to convert to Christianity, while the Serpent's seedline is irredeemable. History Early teachings Valentinus (100–160) promoted a doctrine which is similar to the serpent seed doctrine because it states that Eve mated with the serpent and produced Cain. In his teaching, the serpent was the manifestation of an aeon named Sophia who seduced Eve. The teachings of Valentinus were compiled in the Gnostic Gospel of Philip () where the idea that Eve mated with the serpent, or Satan, and produced Cain, finds its earliest expression. A similar account is recorded in the Gnostic Apocryphon of John which was authored by the Sethians (). Irenaeus recorded a portion of the teaching and denounced it as heresy in his book Against Heresies. Explaining and commenting on the teachings of Valentinus, Irenaeus states: Medieval Judaism The teaching also appeared in medieval Judaica. In his 1957 book Cain: Son of the Serpent, David Max Eichhorn traces the belief that Cain was the son of the union between the serpent and Eve back to early Jewish Midrashic texts which were composed between 800 CE and 1200 CE. Eichhorn identified rabbis who wrote about the topic, including a 9th-century book titled Pirke De-Rabbi Eliezer and the Zohar. In their version, Adam's first wife was Lilith and his second wife was Eve. Lilith became possessed by the spirit of God's wife and rebelled against Adam and became the mother of all demons. Eve was subsequently seduced by the serpent and became the mother a race of evil men. A later folk-version of the serpent seed doctrine was somewhat widespread in European Christianity during the Middle Ages and it ascribed the ancestry of legendary monsters such as Grendel to Cain. The Aramaic Targum Pseudo-Jonathan contains passages referencing the serpent seed concept. The targum was referenced by Rabbi Menahem Recanati (1250–1310) in his Perush 'Al ha-Torah. The age of the writing is disputed. A 2006 analysis by Beverly Mortensen dates Targum Pseudo-Jonathan to the 4th century and regards it as a manual for kohanim. Gavin McDowell's analyses suggested the document