Leviathan is a mythical sea monster of ancient folklore. Ancient tablets discovered at ugarit in the 1930s have confirmed the mythical background of Leviathan, or lôtān, as he is known in these texts ("the coiled one," from the root lwy, to turn or twist). In these texts, where he is called the "fleeing serpent" and "coiled serpent," exactly as in Is 27.1 and Jb 26.13, he is pictured as a seven–headed, evidently serpentlike monster that is slaughtered by baal or his consort Anat [see J. B. Pritchard, Ancient Near Eastern Texts Relating to the Old Testament (Princeton 1955) 137, 138]. It is unfortunate that the nature and activity of the monster are not more prominent in the extant narratives, which, it may be noted, are not cosmogonic in nature.
According to the Old Testament [Ps 73 (74).14] it is not Baal, but Yahweh, who crushed the many–headed Leviathan and fed him to the sharks. The context of the reference in this Psalm shows that here also Leviathan is pictured as a sea monster and seems to indicate that he was destroyed before the organization of the universe (v. 16–17). There is an allusion to the myth, though an obscure one, also in Jb 3.8. In Is 27.1 the apocalyptist, basing himself on Leviathan's double attribute ("fleeing serpent" and "coiled serpent"), seems to have made two monsters out of one and used them to symbolize unidentified political enemies that will be destroyed in eschatological times (cf. Rahab as a symbol of Egypt). In Jb 40.25–41.26 is found a lengthy description of Leviathan, the terrible monster of the deep. The author seems to have found his inspiration in the crocodile for most of the traits he attributes to Leviathan, but some of them he has drawn from his own imagination (e.g., 41.10–13). In this passage, as well an in Ps 103 (104).26, Leviathan has been in large part "demythologized" and merely designates a marine animal, awesome to man, perhaps, but a plaything to Yahweh.
Bibliography: h. gunkel, Schöpfung und Chaos in Urzeit und Endzeit (2d ed. Göttingen 1921). o. kaiser, Die mythische Bedeutung des Meeres in Ägypten, Ugarit, und Israel (Berlin 1959). j. l. mckenzie, "A Note on Psalm 73 (74):13–15," Theological Studies 11 (1950) 275–282.
[l. f. hartman]
"Leviathan." New Catholic Encyclopedia. . Encyclopedia.com. (August 15, 2018). http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/leviathan
"Leviathan." New Catholic Encyclopedia. . Retrieved August 15, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/leviathan