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The world’s first recorded monotheistic religion was established in the 14th century BC and abandoned after only 20 years.

Long before the founding of today's monotheistic religions, the pharaoh, Akhenaten, established a new faith centered around the a sun god, Aten. The priesthoods of Egypt's traditional gods were disbanded. As the sole intermediary for Aten, the Pharaoh's new theology closed of the realm of the dead to all but the royal family. History's first experiment with monotheism ended upon Akhenaten's death. After only twenty years, a radical reversal was made. Traditional temples were reopened, the old ways restored and Atenism was regarded as a great heresy.Source