Nikolai Alexandrovich Berdyaev was a Russian philosopher, theologian, and Christian existentialist who emphasized the existential spiritual significance of human freedom and the human person. Alternative historical spellings of his surname in English include "Berdiaev" and "Berdiaeff", and of his given name "Nicolas" and "Nicholas". Russian paleontologist and Christian apologist Alexander V. Khramov attributes his ideas about an atemporal human fall to Berdyaev and Evgenii Nikolaevitch Troubetzkoy.