I see you refer to El-Daly. I like to read from multiple perspectives; history is not alone written by the victors. That claim is incorrect and keeps you within the abrahamic circles. At least check out his other sons. First step in separating noize, is to find the best sources.
But El-Daly refers to sources, who refer to sources, which isn't available anymore. Besides, you're in the Semitic/Arabic world now: Ibn Wahshiyyah (Abū BakrʾAḥmad bin also called Ali). I like to call him Ali the First, but that's probably not correct.
And there is another dude, who's name i forgot. I need to make a new post once this name pops up again.
Horapollo is also another old source.