You can't call someone left or right if they're authoritarian. Stalin, Hitler, Mao, Castro, Tito, Caesar, William VIII, etc.. If someone makes a decision on how to run a nation, that's one voice. It isn't a movement (left/right are scales of popular belief in terms of social/economic freedoms). To call a single person (left/right) is almost entirely meaningless in the grand scheme of things, and calling a dictator anything but a dictator doesn't advance one's story.
All dictators require control, and how one exercises that said control varies wildly based on their time in history and the levers necessary to exert control. That's the only real figure necessary for dictators. If a lever of control no longer exists, it falls apart. Romans and most earlier empires exerted control by marching huge armies at opposition. Later, European monarchs exerted control largely through social classes re-enforced by the nation's religion. In my poor home of Canada, they had programs to take aboriginal children from their parents to 'learn' the Canadian way of life. Yay, democracies! The pope is a dictator in his own right, though a dictator who's power to control has fallen significantly.
"Heck, just look how the left in the US is rewriting history"
I'm confused here. Can you give me some google juice on this? Specifically, I'd like to know when/where records were deleted / rewritten.