Board Thread:Naruto Discussions/@comment-25122992-20170201160936/@comment-734582-20170201170545

It's implied Sharingan users have photographic memory, so it's likely that Madara simply understood what it read, after he awoke the Rinnegan.

I don't think it's necessarily a special text that requires the Rinnegan, but rather it's written in archaic text that requires a very powerful dojutsu to decipher.