Howard Zinn took Marx's theories literally. Now, they have been digested and the good bits have been taken out. Looking at the history of the discipline, you will notice that Marx's historical work marks a turning point in how historians work. Today, social history is predominant. Sure, Marx was wrong about almost everything he said in substance, but the general methodology was not all bad and has had valuable repercussions.
Howard Zinn took Marx's theories literally. Now, they have been digested and the good bits have been taken out. Looking at the history of the discipline, you will notice that Marx's historical work marks a turning point in how historians work. Today, social history is predominant. Sure, Marx was wrong about almost everything he said in substance, but the general methodology was not all bad and has had valuable repercussions.
I don't know much about historical theories and methadology. However, I'm take a class that deals with it this semester.
However, the reference to Marx was in a Sociology class.
If you want to understand what Marx did in the history of ... history, consider this: if it weren't for Marx, history would still be based entirely on political history and the history of governments and those who run them.