How many people that believe in vampires varies throughout the years, decades, and even centuries. Belief in vampires, as belief in anything, waxes and wanes. The oldest known document with reference to a vampire-like being is a 2400 BC tablet known as ",The Sumerian King List",. Now, even the Sumerians cannot be credited as the first to come up with vampires, they are just the first to write about it. There were no other historically written documents before the Sumerians.