Magic: The Gathering has had a long history of bringing in creatures and characters either from real life or fictional works, albeit with fun new names. The Odyssey card Repentant Vampire, for example, features artwork that is an homage to the character Angel from the television show Buffy the Vampire Slayer.
In some of game's earliest sets, however, some real-life names actually made their way into the game in ways other than an easter egg in the artwork. Arabian Knights, for example, featured the likes of King Suleiman of the Ottoman Empires (via the card Bottle of Suleiman), as well as a number of characters such as Ali Baba, Sinbad, Aladdin, and others from the set's source material, a collection of Middle Eastern folk tales known as One Thousand One Nights.
When Legends was in development for its 1994 release, WotC decided on a good mix of real-life cards to put in as cards. Who were they? Well, among the fictional people there was the Mesopotamian hero Gilgamesh, the Germanic warrior Beowulf, Lancelot (of King Arthur fame), and Greek mythological characters Circe, Achilles, and Jason. Among the real people possibly going in the set, WotC was playing around with the Babylonian King, Nebuchadnezzar, and the Iroquois leader, Hiawatha. And those are just the ones they were willing to name.
However, inclusions of real-life anachronistic personas as creatures proved to be a bit distracting. After all, the fantasy genre allows you to go all over the map of make-believe and still have things make sense because it is all fictional. You start putting real-life figures in there and, well, even if they are ancient, it can still seem political and there's also that risk of misrepresenting a culture or society. Original characters were put back in...except for one that is.
Nebuchadnezzar managed to stay on the roster. How, you may ask, did it make it through? Well, not even Wizards seems to know that one. It somehow made it through playtesting, becoming the first real-life, historical person to be made into a creature card. (No, we're not counting Rasputin Dreamweaver even though there was a real-life Rasputin (Grigori Rasputin) -- he just wasn't of the Dreamweaver line.)
To date, WotC still prefers to avoid naming cards on real-life people. Even lands based on real life places get this treatment. And it doesn't even seem to matter if the names are public domain, like all those different myths. It just tends to be avoided overall if it can be helped.
But one of the few to break that mold was Nebuchadnezzar, which only became a card because it made it through the cracks. Which, honestly, sounds to be about right on par for Magic.