For more information, see the page: memory-alpha (dot) org/en/wiki/Mirror_universe or watch the TOS episode “Mirror, Mirror.”
There are more than two theories of history, but these are the two main paradigms. The traditional view of history is that key leaders and key events make the world go ‘round (think back to grade school, when you had to memorize the dates of battles and who was beheaded during the French Revolution? Which Louis was it?), and the post-modern viewpoint, which argues that the general population living ordinary lives make history. There are many ways to look at history. You can consider it based on economics, geo-politics, scientific revolutions, through ideas such as feminism, urbanization, through the lens of imperialism, etc etc.
I am, if you haven’t noticed, partial to Russian history. I also worked for a stint with an Ottoman history professor, and that empire is absolutely fascinating as well. The Ottoman Empire was organized by the millet system, and historical research to figure out exactly how flexible or strict that was is really interesting. Also, everyone should know about the epic power struggle between Mahmud II and Mehmet Ali Pasha and the intricate geopolitics of that era. I looked at the wikipedia pages for these topics, and there’s a lot to be desired. If you want to get a solid start on Ottoman history go find a hard copy of the Encyclopedia Britannica and read there. Then refer to their bibliography, which will have a list of excellent, high quality academic monographs on the topic.
That was quite an aside.