Egyptian pharaoh (c. 1388 B.C to c. 1362 B.C.). He was born sickly and deformed (with an elongated skull, thin limbs, and prominent hips, breasts, and paunch), and it was believed that he would die young. After he was appointed co-regent with his father, Pharaoh Amenophis III, Amenophis IV (the name he was called) became interested in religion and the arts. He joined the cult of the Aten, a sun god, and married the beautiful Nefertiti.
After his father's death, he took the throne of Egypt and instituted several major reforms. He declared that the Aten was the only god; though he did not suppress worship of other gods, he redirected funds from the old temples to support Atenism. He encouraged a revolution in the arts that emphasized naturalism over idealism (the images made of him at this time showed all of the pharaoh's deformities). He appointed new officials and began work on a new capital called Akhetaten (or Horizon of the Aten) in Middle Egypt. And he changed his name from Amenophis IV to Akhenaten (or Useful to the Aten).
Akhenaten was noted as a very open ruler but a very poor leader. He loved to sit outside in the sun and required that all ceremonies be held outdoors in sunlight. He was very apathetic, extremely blunt, and very close to his mother.
In concentrating all his attention on theology, Akhenaten neglected foreign affairs, losing allies and allowing enemies to encroach on Egyptian territory. Akhenaten's brother, Smenkhare, moved to the capital and became co-regent. The brothers were close friends (some say they were also lovers), despite the fact that Smenkhare was a follower of the cult of Re. Possibly believing that her husband was betraying Atenism, Nefertiti moved to a palace in the northernmost part of the city with her six daughters and Tutankhaten (who may have been another of Akhenaten's brothers). After a plague killed several members of Akhenaten's court, including Smenkhare, Akhenaten fiercely suppressed the other Egyptian gods and, soon after, died.
Tutankhaten succeeded Akhenaten as pharaoh. He reinstituted worship of the old gods and, of course, changed his name to Tutankhamen. When Akhenaten's bloodline died out, all references to his reign were purged from the records, and he became known as "That Thief," if he was mentioned at all. His mummy has never been found.
Akhenaten was one of the first identifiable monotheists in history, so he gets all kinds of rumors and conspiracy theories tied to him. He has been associated with the mythology of the Rosicrucians. Some fringe Egyptologists think he was the pharaoh who tangled with Moses. Some people think his deformities were caused by Marfan's syndrome, Froelich's syndrome, or castration as a youth. Some theorize that he was actually a woman.
Research from GURPS Who's Who, compiled by Phil Masters, "Akhenaten" by Brian C. Smithson, pp. 14-15.