The original playtest file for Legends contained cards for several characters culled from other sources, including:
Hiawatha, the greatest of all American Indian heroes;
Gilgamesh, the ancient king of Babylon;
Beowulf, of Anglo-Saxon epic poem fame;
Lancelot, King Arthur's right-hand man;
Circe, the black sorceress that turned Odysseus into a pig;
Achilles, the fabled Greek charioteer; and
Jason, the captain of the legendary ship Argo.
Steve and Robin eventually decided that the set would be better off without preexisting characters, so they decided to scrap them all in favor of their own unique creations. But when the set was finished, one character from existing lore made it in: Nebuchadnezzar.
Nebuchadnezzar was more that just a legend, he was a real person -- the biblical king of the Chaldean Empire. Aside from the destruction of Jerusalem and Judah, Nebuchadnezzar is best known for his efforts to rebuild Babylon, which became one of the most wondrous cities in the world during his reign. The fabled Hanging Gardens were constructed by Nebuchadnezzar's decree, and he also rebuilt the Temple of Marduk and its ziggurat, which are now referred to collectively as the Tower of Babel.
The card was submitted as "Nebuchadrezzar," which is an alternate spelling of the name. The Editing department changed it to the more common spelling.