Are there moral limits to romanticizing historical figures in art?

For example, a writer might romanticize Robin Hood as the Ragnar Danneskjöld of the Middle Ages. If this is proper, is there an ethical limit as to what kinds of persons one may or may not romanticize, or as to how far one may stretch the historic truth? For example, does it matter if there are still contemporaries of that historic person alive who suffered unjustly because of them? Would it be immoral to ignore this in order to present a fictionalized heroic character?