Century-old modern music

I recently stumbled onto what is considered the first jazz song ever published: “Jelly Roll Blues” — variously said to have been composed in 1902 (which is disputed) , 1905, and 1910 by Jelly Roll Morton. At any rate, the song was first published in 1915, at which time jazz could definitively be said to exist as a musical form bearing that name.

Afro-Creole pianist Jelly Roll Morton began his career in Storyville. From 1904, he toured with vaudeville shows around southern cities, also playing in Chicago and New York. His “Jelly Roll Blues“, which he composed around 1905, was published in 1915 as the first jazz arrangement in print, introducing more musicians to the New Orleans style.^[29]

Here’s the 1915 version:

http://www.youtube.com/watch?v=0qQRF80wIFw&feature=related

Interestingly, the name “Jelly Roll” seems to have had a sexual origin:

Morton was, along with Tony Jackson, one of the best regarded pianists in the Storyville District early in the 20th century. At the age of fourteen, he began working as a piano player in a brothel (or as it was referred to then, a sporting house.) While working there, he was living with his religious church-going great-grandmother and had her convinced that he worked as a night watchman in a barrel factory.

In that atmosphere he often sang smutty lyrics and it was at this time that he took the nickname “Jelly Roll”,^[5] which at the time was black slang for the female genitalia.^[6]

It’s a great song, but what puzzles me more than the salacious etymology of jazz is the difficulty of assigning an specific date to the birth of the genre.

Do we go by the date of writing the first jazz song, or the date of publication?

Assuming Morton wrote the song in or before 1910, jazz may very well be 100 years old.

Or else it soon will be.