HIEROGLYPHICS

Hieroglyphics is the ancient text in that Egyptians would write in, by carving the symbols into rock on walls of buildings. I have researched into hieroglyphics and dispite their existance for centuries it wasn't until 1799 that the rossetta stone was found and the secrets of the symbols began to be revealed and understood by archaeologistis of the present day.

Its downfall came with the religious change into Christianity stopping the hieroglyphics and changing the ancient language through time into Arabic.

This is similar to illustration in the sence that where as hieroglyphics had a code to relay the information to people and what each symbol meant. Pictorial illustration can be difficult to decipher the meaning without any text following it, like in a childrens book for instance. But Illustration is sometimes produced purposly not to be easily understood, if purly pictorial.