This genre of music originated in 'the bronx' run DMC was the artist who invented it in 1896 . there the whole population  was black americans and were poor . it became  very popular in a short time and others like grandmaster flash came into the picture . it was  mainly popular with the blacks because it was a mode to express their hardships , sorrows,etc. gradually its base expanded to more people like Lil wayne ,snoop dogg, eminem , 50 cent etc.but still the majority of singers were black.

the coming of other artist created rivalry and led to creation of subgenres in rap like west-coast rap ,east-coast rap , underground rap.

In the period of 1950 60's rivalries were on a large scale . this led to the formation of  different gangs like' LA Harlem gang' who had their own mark of identification , a crown topped a cross tattooed o top on right arm . if any person other than the gang member had this , he had to face death.

Due to these rivalries artist like tupac , notorious big were shot dead . today these things still continue but in other forms , so called rap wars and of course gang markings .

Similiar kind of game not fully based on this developed by 'rockstar games' called 'san andresas ' which was very popular.