Jazz is a musical genre born between the end of the nineteenth century and the beginning of the twentieth century in the United States of America. Between all the characteristics of the Jazz the most common one is its sonority, in fact the difference between this genre and every other music genre, is the particularity that all the instruments it’s like if they are “loose” between each other, in fact the improvisation is an essential part in all jazz songs.
The improvisation depends and changes a lot respectively at the musician who is playing, and on which feelings he wants to transmit trough the music, in fact this is the motivation for which is really difficult to replicate an improvisation of a past performance.
The origins of this genre starts with the discovery of America, after this there was a really important demand of men for the labor of tobacco, cotton and sugar cane plantations of the large American landowners. So they decided to start buying slaves from Africa and bringing them in the new continent.
During the hard work in the fields, slaves started singing songs in their native language (they didn’t know American) because this was one of the few things permitted by the landowners because they noticed that the singing helped relieving the fatigue of that tremendous work. These songs were the gospels, and a really interesting fact about this type of song is that the rhythm can remember the movement that the slaves had to do with the arms all day long, so it can remember a sort of chant.
The only topic of these songs was absolutely religious (in fact gospel means “god’s word) this because the slaves found lot of relief in the Christianity, this because it promises an eternity life in paradise for the ones who during life were considered the “Unluckiest and outcasts”.
The gospels became the modern jazz (very similar to the one that we know today) at the end of the American civil war, in fact with it, it ends the slavery and we can see the formation of jazz bands all over America, especially in New Orleans and Chicago. Usually these bands were formed by three or more people, and the “basic” instruments were the:
The drums
A piano
A guitar
And in the bigger bands was really common also a trumpet.
Jazz becomes really popular also in Europe after the important 1929 crisis, in fact lots os musicians to work and survive had to leave America and start performing in Europe. Here jazz assumes a really danceable rhythm and we call this form of jazz “Swing”.
The swing obtains really quick an enormous success, that some music studious define it as a different genre from the Jazz, But I prefer calling it Jazz’s subgenre.
The last subgenre that got formed in those years is the “fusion Jazz” that is a mixture between rock music and jazz, like you can imagine also this type of music was formed at the end of the 1930 when the jazz “emigrated” if we can say like that to Europe.

Sources
https://en.wikipedia.org/wiki/Jazz#:~:text=Jazz%20is%20a%20music%20genre,harmony%20and%20African%20rhythmic%20rituals.
https://www.britannica.com/art/jazz