Aton

One of the gods of ancient Egypt, symoblized as the disk of the Sun.

During the 18th Dynasty, king (pharaoh) Amenhotep IV decided that there was only one God, and Aton was that God - perhaps the first occurence of monotheism in recorded history (sometime before 1300 BCE). The Paharaoh even changed his name to Akhenaton. He ordered ancient statues of other gods, and other references to them, destroyed - again, perhaps the first case of book burning in recorded history, certainly the first one done in the name of God.

Akhenaton's successor, Tutankhamon, became the next Pharaoh at the age of 9, and immediately restored the multitude of gods in Egytian religion, as well as the restoration of destroyed statues and temples.

Perhaps the gods appreciated this restoration since Tutankhamon's burial site was the one best preserved till modern times.

Tutankhamon ruled for only 9-10 years, then died.

Some historians like to make a link between this occurrence of monotheism and the development of Judaism, theorizing that perhaps the Jews picked up the whole idea during their slavery in Egypt (that they did spend time in slavery is historical fact).

As with most ancient history, though, no smoking gun can be found to prove or disprove this theory, which leaves the details of the development of Judaism (and hence, Christianity and Islam as well) to faith or opinion.