Hieroglyphics consist of pictures that depict common objects. As a more sophisticated system develops pictures are used to represent sounds so the writing could be read phonetically.
Hieroglyphic developed ins stages, as was the case with all writing systems. At first, only the simplest symbols were developed. Then the number of symbols increased, making it easier to read. It was essentially unchanged for several thousand years until about 500 BC when the number of symbols again increased dramatically. The demise of hieroglyphic writing coincided with the rise of Christianity.
Discovering the scientific advances of the ancient world translating scrolls and other hieroglyphics writings has allowed modern scholars to learn about the achievements of the ancient Egyptians.
For centuries after the close of the Egyptian empire, hieroglyphics were a mystery that no one could read. Then in 1822 Jean Francois Champollion, a brilliant young French linguist discovered the key to reading the Rosetta Stone, a tablet with writing in hieroglyphics, demotic and Greek, Hieroglyphic writing could be deciphered.
Egyptians develop a hieroglyphic system of writing