What factors created a socioeconomic class struggle in the late roman republic?

One of the major factors that created a socioeconomic class struggle in the late roman republic was that the lower classes were given more rights, and could challenge the upper classes more easily. 

Contributing factors  leading  to the harlem renaissance were the great migration of african americans to northern cities, which concentratedambitious  people in places where they could encourage each  other, and the first world war, which had created new industrial work opportunities for tens of thousands of people.