What I mean by the "oldest martial art" is an organized martial art or lineage of martial arts that we have history about from a reliable source including its origins and date that it was designed. I'd like to know how far back can we rewind in the history of martial arts.
Please note that that I am looking for a lineage of martial arts if possible; I'm looking for the oldest art with proof. This art may not be practiced today or greatly altered.
Now I may know that there is not a 100% definite answer to this question, but what is the best answer possible that we can be sure about?