What came first, the atheist or the theist?

[Paul the Human]

No one said, "I do not believe in god" until after someone else said, "There is a god." That much is true. Before that, no one believed in god, since the concept had not been thought up yet. Since atheism is the lack of belief in god... everyone was atheist until the first claim that a god exists came to be. They didn't have a word for it yet, obviously, but we do now. That word is 'atheism'.