Karl Marx wrote in The Communist Manifesto that the history of man had been defined by what?

Karl Marx thought that the history of man had been defined by the Class Struggle.

Also, important to the first statement is that the class that controls the means of production becomes the ruling class. Changes in the situation are by class struggle. With that being said, the class that is being exploited by the ruling class, stages a revolution and becomes the new class owning the means of production.

The Manifesto predicts that soon the workers would overthrow the capitalists.