Over 800 references to the pre-earth existence of mankind have been identified in Jewish and Christian sources from the time of Christ until the sixth century, A.D. Early Hellenistic (Greek) writings also referred to belief in a pre-earth life. However, after the sixth century A.D., mention of a life before mortality virtually disappears from orthodox Jewish, Christian, and Greek writings (Hamerton-Kelley, R.G., Pre-Existence, Wisdom and the Son of Man in the New Testament, Cambridge University Press, 1973).
A premortal existence was discussed by such well known ancient philosophers as Plato, and Christian writers Origen of Alexandria and Justin Martyr. The writings of the ancient Jewish historian Josephus and the Jewish theologian Philo (who claimed that everything he wrote agreed with the Pentateuch) show that belief in a premortal life was evident in Judaism until the 5th century, A.D., which in certain quarters held that the soul longs to return to that premortal existence after earth life (Judische Theologie, 212-228).
Until the sixth century A.D., early Christianity taught that we had a pre-earth life. Then the doctrine of a pre-existence was condemned by the council of Constantinople in A.D. 553. However, Hastings Encyclopedia of Religion and Ethics reports the doctrine of a pre-existence was favored by Origen (the greatest of early church theologians), Justin Martyr, Augustine, Cyril of Jerusalem, Peirius, John of Jerusalem, Rufinius, Nemesius, and the Western Church generally until the time of Gregory the Great (article on pre-existence, p. 239).