From archaeological excavations done across the ancient Afro-Asiatic Dominion, it is clear that there existed a form of writing during the Neolithic period based upon the Thinite script of the Nilo-Saharans (5000-3000 BC). This system of writing consisted of marks made on pottery and the symbols are rather uniform from the Nile to Southern India.
Perhaps the world's oldest known from of writing, the pottery marks have been termed of what some "Proto Saharan" but they also could be termed "Old Nubian."
Many of these symbols correspond to the symbols of the old Arabian scripts, especially Thamudic and Nabataean scripts which mention Horus. Similar symbols are found on Yahu seals from Judah dating to the seventh century B.C.
Related reading: Pottery Marks - Evidence for Early Writing Practices in Thinite Egypt and Early Dynastic Mesopotamia; The Afro-Asiatic Dominion; The Aleph as Ox Head, Thamudic Scripts; The Urheimat of the Canaanite Y; The Proto-Elamite Script; The Genetic Unity of Black African Elamite, Dravidian and Sumerian Languages by Clyde A. Winters; 70,000 Year Old Settlement Discovered in Sudan