How Communication Evolved From Pictures to Letters

• The Greeks used messenger pigeons to deliver the results of the first Olympiad in the year 776 B.C. They also established a library in 530 B.C.
• Near the end of the B.C. period, systems of long-distance communication became more commonplace. In Egypt and China, messenger relay stations were built. They used human messengers on foot or horseback.
• In the year 14, the Romans established the first postal service. Mail delivery systems were already established in India and China.

• In 105 China, an official Cai Lung suggested using "the bark of trees, remnants of hemp, rags of cloth, and fishing nets" for writing on instead of heavier bamboo or costlier silk material.
• The Chinese followed that up with the invention of the first clay moveable type for printing paper books between 1041 and 1048.
• Between 1436 and 1450, Gutenberg's printing press was developed. It introduced key innovations such as oil-based ink, mechanical movable type, and adjustable moulds.

In 1835, inventors Joseph Henry and Edward Davey independently demonstrated electromagnetic relay, where a weak electrical signal can be amplified and transmitted across long distances. Cooke and Wheatstone invented the telegraph shortly after.

A few years later, Samuel Morse developed a version that sent signals from Washington D.C. to Baltimore. Afterwards, he developed a system of signal-induced indentations that correlated to numbers, special characters, and letters of the alphabet, known as the Morse code.

The next idea to explore was finding a way to transmit sound to far distances. Alexander Graham Bell laid out the underlying technology for electromagnetic telephones and was granted a patent in 1876 for his improvements in telegraphy.

This introduced a new problem: what if you were not available if someone tried to call you? At the turn of the 20th century, Danish inventor Valdemar Poulsen invented the telegraphone, a device for recording and playing back the magnetic fields produced by sound.