The elegant pictorial writing system of the ancient Egyptians—known as hieroglyphics—has fascinated generations of archeologists. Its precise origins are uncertain. One ancient Egyptian legend holds that the god Thoth handed the gift of writing to a few chosen scribes. A more prosaic modern theory suggests that they derived from rock pictures produced by prehistoric hunting societies wandering the desert.

Now, a new discovery may hold some clues as to how carved images evolved into a formal writing system. According to a Facebook post by the Egyptian Ministry of Antiquities, a new rock inscription site discovered around 60 km south of Luxor in the village of El-Khawy “helps in understanding the development of a system of graphic communication that sets the stage for the appearance of true hieroglyphic writing.”

A rock panel displaying four signs, discovered on a joint Yale and Royal Museums of Art and History (Brussels) expedition, features depictions of a bull’s head on a short pole followed by two back-to-back saddlebill storks with a bald ibis bird above and between them. Yale University’s John Coleman Darnell said in an article on Yale’s website that they constitute “some of the earliest—and largest—signs from the formative stages of the hieroglyphic script.”

According to the Egyptian antiquities ministry statement, “These symbols are not phonetic writing, but appear to provide the intellectual background for moving from depictions of the natural world to hieroglyphs that wrote the sounds of the ancient Egyptian language.”