Hydraulic Telegraph of Aeneas: World’s First Telecommunications Device Invented by Ancient Greeks

Advances in technology have greatly changed the way we live our modern lives compared to those of our ancestors. One type of technology that most of us may take for granted is the ability to practice telecommunication.

Telecommunication goes back a lot further than we might expect. While this word has become synonymous with television broadcasting and phone communication, it describes any communication system over a distance. One particular ancient telecommunication version was the hydraulic telegraph used in ancient Greece around 350 B.C.

First Telecommunication Device

A hydraulic telegraph is designed to use water and mechanical devices to send information over long distances. The earliest version of this invention was made by ancient Greek writer and inventor Aeneas Tacticus of Stymphalus, one of the earliest Greek writers on the art of war. It was a semaphore system used during the First Punic War to send messages between Sicily and Carthage.

The apparatus is recognized as the first telecommunications device in the world. It was designed to send messages across Alexander the Great's vast empire. The mechanism of the hydraulic telegraph is described in Aeneas' work on sieges, "Poliorcetika," which Greek historian Polybius retrieved.

This system includes the successful transmission of pre-agreed messages based on the absolute simultaneity between the transmitter and receiver operators. The operators had to be very careful not to send the wrong messages, as it could be disastrous during wars.

How Did the Hydraulic Telegraph Work?

The mechanics behind this device were simple but ingenious. Numerous telecommunication groups of beacons are placed on carefully chosen hills in ancient Greece. The hydraulic telegraph was operated by messengers who stood at a particular hill and used clay or metal cylindrical containers or jars of equal size. The containers were filled with water up to one wide and three cubits high.

Each jar contains a floating cork, which is a little narrower than the mouth of the container. Attached to the float's center is a rod divided into equal parts inscribed with the same pre-agreed messages. These messages include 'Cavalry arrived in the country,' 'Heavy infantry,' 'Light-armed infantry,' 'Infantry and cavalry,' 'We need wheat,' 'Cyclical movement,' and so on.

The transmitter would lift a burning torch to signal the receiver to send the message. This will be confirmed by the rise of the torch from the receiver. Afterward, the transmitter would lower his torch to signal the simultaneous opening of both taps on their apparatus.

As the water drained, the rods with the messages descended. When the desired message to be sent appeared at the rim of the transmitter's device, he would raise the torch again to signal the receiver for the simultaneous interruption of the outflow.

Since the devices are geometrically similar, the desired message also appeared on the receiver's device. In the event of intrusion or enemy approaching, they would only witness the torch flashes without intercepting the message in any way.