Phryctoria

Phryctoria (Greek: φρυκτωρία) was a semaphore system used in Ancient Greece. The phryctoriae were towers built on selected mountaintops so that one tower (phryctoria) would be visible to the next tower (usually 20 miles away). The towers were used for the transmission of a specific prearranged message. One tower would light its flame, the next tower would see the fire, and light its own.

In Aeschylus tragedy Agamemnon, a slave watchman character learns the news of Troy's fall from Mycenae by carefully watching a fire beacon. Thucydides wrote that during the Peloponnesian War, the Peloponnesians who were in Corcyra were informed by night-time beacon signals of the approach of sixty Athenian vessels from Lefkada. When Cnemus attacked Salamis Island, the Salaminians informed the Athenians and asked for help by beacon-fires.

Polybius wrote that Pyrsourídas (Πυρσουρίδας) were beacons established by Perseus of Macedonia across the entire region, enabling him to receive rapid reports about events in different locations. The Byzantine encyclopedia Suda notes that this system was similar to the later Byzantine beacon network.