1911 Encyclopædia Britannica/Apollyon

APOLLYON, the “foul fiend” who assaulted Christian on his pilgrimage through the Valley of Humiliation in John Bunyan’s great allegory. The name (Gr. Άπολλύων), which means “destroyer” (ἀπολλύειν, to destroy), is taken from Rev. ix. 11, where it represents the Hebrew word Abaddon (lit. “place of destruction,” but here personified). The identification with the Asmodeus (q.v.) of Tobit iii. 8 is erroneous.