What strange disease did King Nebuchadnezzar temporarily have?

Answer 1

In Daniel 4:33, King Nebuchadnezzar certainly does seem to have been temporarily struck with a strange disease: "The same hour was the thing fulfilled upon Nebuchadnezzar: and he was driven from men, and did eat grass as oxen, and his body was wet with the dew of heaven, till his hairs were grown like eagles' feathers, and his nails like birds' claws."

In understanding this, we should recognise that scholars (for example, Leonard J Greenspoon, author of Between Alexandria and Antioch: Jews and Judaism in the Hellenistic Period, The Oxford History of the Biblical World, p322) say that the Book of Daniel was a second-century-BCE Jewish novel. The author was not writing history and was aware that these things never happened and that the hero of the story never lived, and his intended audience had the same knowledge, even if the book eventually came to be accepted as historical. The popularity of the book came in part from the way it mocked and ridiculed the enemies of the Jews and in part from its demonstration of the power of the Jewish God. King Nebuchadnezzar never ate grass like an ox and never grew his hair like eagle's feathers, so he was struck down with no strange disease to cause this.

Answer 2

King Nebuchadnezzar suffered from a mental illness that made him behave like an animal, known as lycanthropy. This illness caused him to live in the wild like a beast, eating grass and having unkempt hair and nails. After a period of time, he was cured and his sanity was restored.

Answer 3

He lost his sanity and behaved like an animal, as predicted. See also:

Accuracy of the Hebrew Bible