Why was Sigmund Freud so obsessed with Egypt?

Twenty years ago, I visited the ancient Egyptian city of Amarna with a party of American journalists. Even in those days this place, near Asyut on the Middle Nile, was regarded as a dodgy destination for western tourists. As a tribute to the value of an entire CBS television crew as a terrorist target, we were accompanied by a squad of heavily armed, black-clad Egyptian special forces.