A sea serpent or sea dragon is a type of dragon described in various mythologies, most notably Greek (Cetus, Echidna, Hydra, Scylla), Mesopotamian (Tiamat), Hebrew (Leviathan), and Norse (Jörmungandr).
Mythology
The "Drachenkampf" mytheme, the chief god in the role of the hero slaying a sea serpent, is widespread both in the Ancient Near East and in Indo-European mythology,
e.g. Lotan and Hadad, Leviathan and Yahweh, Tiamat and Marduk (see also Labbu, Bašmu, Mušḫuššu), Illuyanka and Tarhunt, etc. The Hebrew Bible also has less mythological descriptions of large sea creatures as part of creation under God's command, such as the Tannin mentioned in Book of Genesis 1:21 and the "great serpent" of Amos 9:3. In the Aeneid, a pair of sea serpents killed Laocoön and his sons when Laocoön argued against bringing the Trojan Horse into Troy.
In antiquity and in the bible, dragons were imagined as huge serpentine monsters, which means that the image of a fire -breathing dragon with four /two legs and wings came much later—in the late Middle Ages ; Most of stories say that they live in the sea, the Babylonian myths of Tiamat, the myth of the Hydra, Scylla, Cetus and Echidna in the Greek mythology and maybe even the Leviathan, confirm that.
In Norse mythology, Jörmungandr, or "Midgarðsormr" was a sea serpent so long that it encircled the entire world, Midgard. Some stories report of sailors mistaking its back for a chain of islands. Sea serpents also appear frequently in later Scandinavian folklore, particularly in that of Norway.In 1028 AD, Saint Olaf is said to have killed a sea serpent in Valldal, Norway, throwing its body onto the mountain Syltefjellet. Marks on the mountain are associated with the legend.
