Akhenaten's Monotheist Experiment
The pharaoh Akhenaten did what no ruler had dared: he abolished Egypt's crowded family of gods for a single one, the sun-disk called the Aten, built a brand-new capital in the desert to worship it, and had the old gods' names chiseled off monuments. Within a few years of his death it all collapsed — his city abandoned, his god discarded, his own name struck from the king-lists as a heretic. A faith imposed from the top, spreading and then violently reversed almost at once: the ideological pattern in fast-forward, and an early lesson that a new creed usually provokes a fierce restoration of the old.
A belief system rises, spreads, institutionalizes, and then schisms — changing the rules people accept as legitimate.