Phryctoria

Lore & Background

The phryctoriae were towers built on selected mountaintops so that one tower would be visible to the next, usually 20 miles away. A beacon was called phryctos (plural phryctoi), and the person in charge of beacon signaling was called phryctoros.

Reader's Guide

Phryctoria represents an early form of optical communication that allowed the rapid transmission of prearranged messages across long distances in Ancient Greece. The system was used in various historical contexts: in the Iliad, Homer describes beacons lit atop a city at sunset after battle to summon help; in Aeschylus' tragedy Agamemnon, a watchman learns of Troy's fall by watching a fire beacon; Herodotus records beacons on Sciathus alerting Greek forces at Artemisium of the Persian fleet's arrival; and Thucydides notes that during the Peloponnesian War, the Peloponnesians in Corcyra were informed by night-time beacon signals of approaching Athenian vessels. Philip V of Macedon employed a network of beacon fires to monitor enemy movements and coordinate responses. The system was limited, however, as it could only convey a few prearranged messages and could not communicate unexpected events. Later, Greek engineers Cleoxenes and Democletus invented the pyrseia, which used two groups of five torches to encode letters of the Greek alphabet, a system later perfected by Polybius. The Byzantine encyclopedia Suda notes that beacons were used to communicate with nearby allies, with a steady light indicating friends and a moving light signaling enemies.

Did You Know?

• A beacon was called phryctos, and the person in charge was called phryctoros.
• Polybius described an improved method by Aeneas Tacticus using two identical earthenware vessels filled with water to convey messages.
• In the 2nd century BC, Greek engineers Cleoxenes and Democletus invented the pyrseia, using two groups of five torches to encode Greek alphabet letters.