Class struggle, simply put is the tension or antagonism which exists in society due to competing socioeconomic interests and desires between people of different classes.
The idea was first propagated by Karl Marx and Friedrich Engels in designing the Communist Manifesto. The Manifesto published in February 1848, was intended as a definitive programmatic statement of the Communist League; a German revolutionary group of which Marx and Engels were the leaders. Few months after its publication, Europe was to erupt in social and political turmoil, and the Manifesto reflected the political climate of the time.