Apelles was a mid-2nd century Gnostic Christian. He was a disciple of Marcion, probably at Rome, but left (or was expelled from) the Marcionite society. Tertullian writes that this was because he had become intimate with a woman named Philumena who claimed to be possessed by an angel, who gave her 'revelations' which Apelles read out in public.
Apelles then went to Alexandria, where he developed his doctrine, a modified Marcionism, which (according to Tertullian) admitted that Christ possessed true human flesh but continued to deny the nativity.
Apelles wrote a book entitled Syllogisms ('reasonings') though the word itself suggests that Apelles may have intended to oppose Marcion's Antitheses, which set the Old Testament and the New Testament against each other. He is last heard of in Rome in the last portion of the 2nd century AD.
Apelles' followers, known variously as the Apellitae, Apelliacos or Apelleasts, are likewise mostly unknown. Tertullian wrote a tract against them which has not survived. Ambrose of Milan in the 4th century directs some of his comments in his De paradiso (On the Garden of Eden) against this sect, but whether the sect was still active or whether Ambrose had merely copied another now lost work of Tertullian on the same subject is unknown.
Tertullian mentions a teaching of this sect that flesh was constructed for seduced souls by a certain 'fiery prince of evil'. Additionally, it was among their beliefs that the body of Christ was composed of earthly elements, and, rather than ascending bodily into heaven, his body dissolved back to the elements after his death. This seems related to the sort of gnostic ideas held by Basilides or Valentinus. Later Marcionite ideas described by the Armenian Eznik (or Yeznik Koghbatsi) seem similar to this.
This article incorporates text from a publication now in the public domain: Smith, Philip (1870). "Apelles". In Smith, William. Dictionary of Greek and Roman Biography and Mythology. 1. p. 223.