Most of what is known of history in our world is written, however without modern inventions how much would truly be known of events form thousands of years ago. Heck even with modern inventions how sure are we that we have the correct information of how things transpired three thousand years ago.
In this world there are two forms of gathering knowledge both as unreliable as the next. Stories and Fables as passed down through the generations perhaps written down, perhaps by word of mouth. They are easily open for interpretation and are useful for general ideas at best. However on the other side you have direct first hand accounts from creates like the Hag. This information is much more reliable, but the question is are they lying or not sharing the whole truth.