Hieroglyphs are symbols in any writing system that are used to describe an object, or an idea. For example a symbol of a four legged creature with big teeth could be used to describe a lion, instead of writing the word lion, and a symbol of a star could be used to indicate night-time. Hieroglyphs are commonly associated with ancient Egyptian times from 3300BC.
The word Hieroglyph comes from the Greek words “hieros” meaning holy, and “glyphe” meaning writing. The Egyptians had over 800 symbols to represent object and ideas. Glyphs are divided into two groups, those representing sounds (phonograms) and those representing objects/ideas (ideograms).
Similar use of hieroglyphs occurred in China, Mesopotamia and the Americas but these were not related to Egypt. So even in the earliest days of codified visual communication, there were defined languages and ways of writing messages and information.
Egyptian hieroglyphs were only fully deciphered using the Rosetta Stone, which is a stone carved in 196BC. The stone contains messages from a group of priest praising the pharaoh. These messages were written in glyph, Greek and Demotic, all three being scripts in use in Egypt at the time. This was so priests, government officials and rulers of Egypt could all read what it said. The stone wasn’t translated until 1822 by Jean-Francois Champollion. Champollion could read both Greek and Coptic and was able to decipher seven demotic signs in Coptic. Using these signs he was able to translate the hieroglyphs and then make educated guesses about what other symbols stood for.
By around 1700BC a subset of Egyptian glyphs had been adapted by Semitic speaking people to represent the sounds of their language. This is known as Proto-Sinaitic script as is thought of as the first alphabetic writing system. Because there were only 22 symbols to learn and remember, it was very accessible and therefore spread widely and easily. By the 8th century BC this alphabet had spread to Greece and was adapted to record the Greek language. The Greek alphabet is the basis for for other alphabets including the Latin alphabet (which spread across Europe) and Cyrillic (which is the basis of modern Russian.)