Knight claims that in the first five or six centuries of Christianity, there were six known theological schools, of which four (Alexandria, Antioch, Cesarea, and Edessa or Nisibis) were Universalist, one (Ephesus) accepted conditional immortality, and one (Carthage or Rome) taught the endless punishment of the lost. The Schaff-Herzog Encyclopedia of Religious Knowledge, 1953, vol. 12, p. 96; retrieved 30/04/09
Talbott, Thomas, "Heaven and Hell in Christian Thought", The Stanford Encyclopedia of Philosophy (Spring 2017 Edition), Edward N. Zalta (ed.), forthcoming <https://plato.stanford.edu/archives/spr2017/entries/heaven-hell/> "Theists who accept the traditional idea of everlasting punishment, or even the idea of an everlasting separation from God, must either reject the idea that God wills or desires to save all humans and thus desires to reconcile them all to himself (see proposition (1) in section 1 above) or reject the idea that God will successfully accomplish his will and satisfy his own desire in this matter "
Richard Bauckham "Universalism: a historical survey" (@ theologicalstudies.org.uk), Themelios 4.2 (September 1978): 47–54. "Here and there, outside the theological mainstream, were some who believed that the wicked would be finally annihilated (in its commonest form. this is the doctrine of 'conditional immortality')." "Since 1800 this situation has entirely changed, and no traditional Christian doctrine has been so widely abandoned as that of eternal punishment.3 Its advocates among theologians today must be fewer than ever before. The alternative interpretation of hell as annihilation seems to have prevailed even among many of the more conservative theologians."
Smith, Jane I. (1981). The Islamic understanding of death and resurrection. Haddad, Yvonne Yazbeck. Albany: State University of New York Press. p. 93. ISBN0873955064. OCLC6666779.
