The original melody was written by World's Fair entertainment director Sol Bloom for use in an attraction called A Street in Cairo. (Bloom did not copyright the music; later songwriter James Thornton would added lyrics to the tune.)
But as popular and ubiquitous as the song would become, it was the accompanying dancing (introduced as "The Algerian Dancers of Morocco") that gained the most notoriety.
In addition to "belly dancing," people also referred to her act as "the shimmy and shake" and "the hoochy-coochy." It is said that her performance for Mark Twain at the Fair caused the great American humorist to suffer a heart attack.
Fahreda Mazar Spyropoulos was arrested by New York City police three years after the Fair. Newspaper reports claimed Little Egypt was dancing the the hoochy-coochy while in the nude at a stag party thrown by the grandson of circus legend P.T. Barnum.