History: Fiction or Science?: Russia. Britain. Byzantinium. Rome

Ancient history is, first of all, a written history based on the following sources: documents, manuscripts, printed books, paintings, monuments, and artifacts. When a school textbook tells us that Genghis Khan in year XXX A.D or Alexander the Great in the year YYY B.C. have each conquered half of the world, it means only that it is so said in some of the written sources. Seemingly simple questions practically never have clear, unambiguous answers. When were these sources written? Where and ...