Mortalism 2: Early Christian beliefs
The earliest post-apostolic Christian confessions of faith do not refer to heaven or hell, but do mention the resurrection. Most writers from the first to the seventh century believed in an immortal soul and eternal torment in hell.  
Soul sleep or soul death was occasionally understood to be followed by eternity in heaven or hell subsequent to the resurrection. Conditionalism was preserved by early Christians such as Arnobius,   and among Syrian Christians such as Aphrahat,  Ephrem,   Narsai,  and Jacob of Sarug.  
 The first century ‘Didache’ and the ‘Old Roman Symbol’, which came to be known as the ‘Apostles’ Creed’.
 ‘Concerning its nature, many early fathers, including the apologist Justin (Dial 45.4) and the Latin fathers Tertullian (Deres 5ff) and Jerome (cf. Ep 119), assumed a fiery hell.’, Bromiley, ‘Hell’, in Bromiley (ed.), ‘The International Standard Bible Encyclopedia’, volume 2, p. 677 (rev. ed. 1988).
 ‘While we freely admit that there are indications that some of the early fathers believed in the final annihilation or salvation of the wicked, it is clear that the majority of fathers believed in a conscious afterlife and eternal punishment.’, Morey, ‘Death and the Afterlife’, p. 60 (1984).
 The belief that people still exist in some non-physical form after death, but remain completely unconscious.
 The belief that people do not exist at all after death.
 ‘Some have believed in the annihilation of the wicked after they should have undergone just punishment proportioned to their sins. This supposition has had a considerable number of advocates. It was maintained, among others, by Arnobius, at the close of the third century, by the Socini, by Dr. Hammond, and by some of the New England divines.’, Alger, ‘The Destiny of the Soul: A Critical History of the Doctrine of a Future Life’, p. 546 (14th ed. 1889).
 ‘The theory of annihilationism in which the wicked pass into nonexistence either at death or the resurrection was first advanced by Arnobius, a 4th-century “Christian” apologist, according to standard reference works such as Baker’s Dictionary of Theology (p. 184).’, Morey, ‘Death and the Afterlife’, p. 199 (1984).
 ‘Already in the fourth century Arnobius taught the annihilation of the wicked.’, Hoekama, ‘The Bible and the Future’, p. 266 (1994).
 ‘On the subject of the fate of souls after death. Aphrahat insists – as does Ephrem – “that as yet no one has received his reward. For the righteous have not inherited the Kingdom, nor have the wicked gone into torment” (8.22; fc. 20). At present, the dead simply “sleep” in their graves, which are collectively referred to as Sheol, or the underworld. Their capabilities for activity and experience are, apparently, almost non-existent, “for when people die, the animal spirit is buried with the body and sense is taken away from it, but the heavenly spirit they receive [i.e. the Holy Spirit, given in baptism] goes, according to its nature, to Christ” (6.14). Aphrahat, however, seems to ascribe to the dead a kind of anticipatory consciousness of their own future which is akin to dreaming in earthly sleep.’, Daley, ‘The hope of the early church: a handbook of patristic eschatology’, p. 73 (1991).
 ‘The wicked will be sent back to Sheol, the real of Death under the world (22.17.24; cf. 6.6), where they will be punished in the measure and the way that their sins deserve – some in “outer darkness,” others in unquenchable fire, others by simple exclusion from the presence of God (22.18-22).’, ibid., p. 73.
 ‘Ephrem, too, conceives of the time between our death and the second coming of Jesus as a “sleep,” a period of inactivity in virtually every aspect of human existence. Because his anthropology is more highly developed than Aphrahat’s, and because he is so insistent – in contrast to Bardaisan and other earlier, more dualistic Syriac writers – that the human person needs both body and soul to be functional, Ephrem seems to imagine that this sleep as [sic] deprived even of the “dreaming” Aphrahat mentions. For Ephrem, the soul without the body is “bound,” “paralyzed” (CN 476.6); it is like an embryo in its mother’s womb or like a blind or deaf person: “living, but deprived of word and thought” (HP 8.4-6).’, ibid., p. 74.
 ‘Because of his insistence on the positive role of the body in human life and its necessity for a full human existence (e.g., CN 47.4), Ephrem sees eschatological reward and punishment as delayed until the resurrection of the dead. Resurrection will begin when souls are “awakened” from their sleep by the angel’s trumpet and the commanding voice of God (CN 49.16f.).’, ibid., p. 75.
 ‘Ephrem’s picture of Gehenna is less detailed and more traditional than his picture of heaven. The damned there seem to suffer most from their awareness that they have lost all hope sharing in beauty and happiness (HP 2.3f.; 7.29).’, ibid., p. 76.
 ‘Following in the tradition of Ephrem and Aphrahat, as well as that of Theodore of Mopsuestia, Narsai assumes that the souls of the dead do not receive the reward or punishment for their deeds until they are reunited with their bodies in the resurrection; until then, they must all wait in Sheol, the earthly place of the dead, in a state of conscious but powerless inactivity that Narsai refers to as a “sleep.”‘, ibid., p. 174
 ‘The Nestorian Narsai described the soul and the body as a pair of inseperable lovers who could not live the one without the other. From the moment that her lover deserted her, he recounts, nephesh lost her speech and fell into a deep slumber. In spite of this, even in this state of forced inertia, she maintained her essential characteristics: her galloping intellect, her acute judgement, the emotions that open up a view in the world. The reason that all her faculties had ceased to function is that they had no more any purpose to serve, since the body for the sake of which they operated was no longer there. Nephesh recovered her sentience and her speech at the end of time when, together with the body, she rose to give an account for her deeds. Till then she felt no pain or joy. The vague knowledge she had of what was in store for her scarcely disturbed her peaceful sleep.’, Samellas, ‘Death in the eastern Mediterranean (50-600 A.D.): the Christianization of the East: An Interpretation’, Studien Und Text Zu Antike Und Christentum, pp. 56-57 (2002).
 ‘His eschatology remains within the Syriac tradition. Thus he speaks often of death in personified terms, as the captor of an enslaved human race or as an insatiable glutton; although Sheol, where the dead now exist, is a dark place of sleep. Jacob also describes the experience of death as a dangerous journey across a sea of fire.’, Daley, ‘The hope of the early church: a handbook of patristic eschatology’, p. 175 (1991).
 ‘On the influence of hypnopsychism on the theology of Jacob of Sarug see M. D. Guinan, “Where are the dead? Purgatory and Immediate Retribution in James of Sargu,” in Symposium Syriacum 1972, pp. 546-549.’, Samellas, ‘Death in the eastern Mediterranean (50-600 A.D.): the Christianization of the East: An Interpretation’, Studien Und Text Zu Antike Und Christentum, p. 56 (2002).
 ‘The doctrine of the ‘sleep of the soul’ after death, a Syrian tradition held in common with Ephrem, Narsai and others’, Murray, ‘Symbols of church and kingdom: a study in early Syriac tradition’, p. 279 (2006).
 ‘In virtually every period of Byzantine history, critical voices denied that the souls of the dead could involve themselves in the affairs of the living or intercede on their behalf in heaven. Based on a more unitive, materialist notion of the self as irreducibly embodied, some thinkers argued that the souls of the dead (sainted or otherwise) were largely inert, having lapsed into a state of cognitive oblivion and psychomotor lethargy, a condition sometimes described as a state of “sleep” in which the soul could only “dream” of its future punishment or heavenly reward. Still others argued for the outright death of the soul, which, they claimed, was mortal and perished with the body, and which would be recreated together with the body only on the day of resurrection.’, Constas, ‘”To Sleep, Perchance to Dream”: The Middle State of Souls in Patristic and Byzantine Literature’, in Talbot (ed.), ‘Dunbarton Oaks Papers’, No. 55, p. 94 (2001).
 ‘Till the end of the sixth century and beyond, Christians in Nisibis and Constantinople, Syria and Arabia adduced Leviticus 17:11 which states that “The soul of the whole flesh is the blood” to argue that the soul after death sank into non-existence, that it lost its sensibility and stayed inert in the grave together with the body.’, Samellas, ‘Death in the eastern Mediterranean (50-600 A.D.): the Christianization of the East: An Interpretation’, Studien Und Text Zu Antike Und Christentum, pp. 55-56 (2002).
 ‘others arose in Arabia, putting forward a doctrine foreign to the truth. They said that during the present time the human soul dies and perishes with the body, but that at the time of the resurrection they will be renewed together.’, Eusebius (a contemporary), ‘Ecclesiastical History’ (6.37.1), NPNF2 1:297.
 ‘It is unclear if Arabian thnetopsychism [‘soul death’] is related to the Syriac tradition of the soul’s dormition [sleep] espoused by writers like Aphrahat (d. ca. 345), Ephrem (d. 373), and Narsai (d. 502), according to whom the souls of the dead are largely inert, having lapsed into a state of sleep, in which they can only dream of their future reward or punishments.’, Constas, ‘”To Sleep, Perchance to Dream”: The Middle State of Souls in Patristic and Byzantine Literature’, in Talbot (ed.), ‘Dunbarton Oaks Papers’, No. 55, p. 110 (2001).
 ‘In his comments on Aphraates, [Aphrahates, a Syrian Christian sage] Braun suggests that he must have been acquainted with contemporaneous rabbinic teaching as to the condition of the soul and body after death. In much the same vein Redepenning thinks that the ‘heresy of the Arabians,’ which caused the dissension that Origen had to settle, was none other than a bit of Jewish tradition which the Church had taken over’, Gavin, ‘The Sleep of the Soul in the Early Syriac Church’, Journal of the American Oriental Society (40.116), 1920.
 ‘we can see that its connections are Jewish and perhaps also Persian.’, Murray, ‘Symbols of church and kingdom: a study in early Syriac tradition’, p. 279 (2006).
 ‘in VIII.397.15 he [Aphrahat] says ‘our faith teaches us‘ the doctrine of the sleep of the soul after death, which seems to come from various but ultimately Jewish sources‘, ibid., pp. 22-23.
 ‘Gouillard notes that variations of thnetopsychism [‘soul death’] and hypnopsychism [‘soul sleep’] existed alongside the views of the official church until the sixth century when they were resoundingly denounced by Eustratios.’, ibid., p. 111.
 ‘Thnetopsychism [‘soul death’] continued to challenge the patience and ingenuity of church officials, as evidenced by writers such as John the Deacon, Niketas Stethatos, Philip Monotropos (Dioptra, pp. 210, 220), and Michael Glykas, all of whom are keenly interested in the survival of consciousness and memory among the souls of the departed saints. John the Deacon, for example, attacks those who “dare to say that praying to the saints is like shouting in the ears of the deaf, as if they had drunk from the mythical waters of Oblivion” (line 174).’ ibid., p. 111.
 ‘The Syriac tradition of the soul’s “sleep in the dust” (Job 21:26), with its links to the Old Testament and Jewish apocalyptic, stands as a corrective to overly Hellenized views of the afterlife, and was canonized at a Nestorian synod in the eighth century (786–787) presided over by Timothy I (d. 823), who rejected anything else as blatant Origenism.’, ibid., p. 111.