It is probably fair to say, that New Orleans can be singled out as birthplace of the Jazz. It provided a unique combination of cultures, especially it had a large Creole population, free Americans which had originated from the West Indies.
An important point in the creation of Jazz music was when New Orleans shifted from being a very open, i.e. Creoles and Whites lived together, to a strictly separated (“equal but separate”) society, which forced the Creoles to move over to the poor African American section of the town. The well educated, European influenced Creoles started playing with the African rooted Blacks.
The influences from the Blues, Chorals and Marching Music were thrown together and Marching Bands started playing “offbeat” sounds, i.e. added syncopation to their music. However, they still followed the music sheets and there was hardly any improvisation.
One of the first central figures in Jazz was Buddy Bolden, who added elements of the Blues into the mix. According to the legend, he could attract large crowds with his cornet, he apparently had a very strong and distinctive sound. This can not be checked anymore as unfortunately, no records from Buddy Bolden seem to have been made or have survived.
The pianist “Jelly Roll” Morton was probably the first one to work the Jazz in a systematic fashion and is considered to be the first arranger of Jazz music. He claimed, as many others, to be the inventor of the Jazz music.
Not only African-Americans and Creoles, like Sidney Bechet and the young Louis Armstrong gave important impulses to the development of the Jazz, a white combo with the name “Original Dixieland Jass Band” (ODJB) made the first Jazz record (however, there are some arguments who was first actually, but ODJB is very often cited as having been the first). So far only classical (European) music had been recorded for the so called “Talking Machines”. The ODJB record was a massive hit and made Jazz popular across the country. Another important white musician was Bix Beiderbecke, a Jazz cornetist and one of the most influential jazz soloists of the early years.
Europe got its first real dose of Jazz music with the first World War, when American Marching Bands brought the ragtime sound, i.e. marching music played with syncopation, over to Europe. After the war, the ODJB toured Europe as well.
A typical band from that “Traditional Jazz” era consists of a frontline with trumpet/cornet, trombone and clarinet supported by a rhythm section which includes a guitar / banjo, bass / tuba and drums.
While it became Jazz when all the ingredients, most notably syncopation and improvisation, were added to the mix, the improvisation was a collective one at the beginning of the Jazz history. The nowadays typical solo improvisations were introduced later, Louis Armstrong being one of the first to push for his solos.
Looking back almost a 100 years later to that early phase of Jazz, for me it is certainly special that Jazz at the beginning of the last century was a rebellion. Parents had the same reactions when their kids were listening (or worse – playing) Jazz music, as they had later with Rock’n’Roll and then with Marilyn Manson. A few of the early Jazz musicians were kicked out from home, when their parents found out that they played in a Jazz combo. The only acceptable music then was European classical music. Jazz broke the rules, as well musically as socially. Improvisation was more important than composition, performer more than composer and it questioned the conventional white, European music structures.