, Devon, England Historically, beacons were fires lit at well-known locations on hills or high places, used either as
lighthouses for
navigation at sea, or for signalling over land that enemy troops were approaching, in order to alert defenses. As signals, beacons are an ancient form of
optical telegraph and were part of a
relay league. Systems of this kind have existed for centuries over much of the world. The ancient Greeks called them
phryctoriae, while beacons figure on several occasions on the
column of Trajan. In imperial China, sentinels on and near the
Great Wall of China used a sophisticated system of daytime smoke and nighttime flame to send signals along long chains of beacon towers. Legend has it that
King You of Zhou played a trick multiple times in order to amuse his often melancholy concubine, ordering beacon towers lit to fool his vassals and soldiers. But when enemies, led by the
Marquess of Shen really arrived at the wall, although the towers were lit, no defenders came, leading to King Yōu's death and the collapse of the Western Zhou dynasty. However, in reality the Great Wall did not exist until long after King You's death.
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. In the 9th century, during the
Arab–Byzantine wars, the
Byzantine Empire used a
beacon system to transmit messages from the border with the
Abbasid Caliphate, across
Anatolia to the
imperial palace in the Byzantine capital,
Constantinople. It was devised by
Leo the Mathematician for Emperor
Theophilos, but either abolished or radically curtailed by Theophilos' son and successor,
Michael III. This system was notable for being able to send different messages. To do this it used synchronized clocks and the knowledge of the longitudinal difference between the first and last stations. The practical efficacy of this system has been challenged, and although it probably functioned it was also a prestige technology in part of Abbasid-Byzantine intellectual competition. In the Nordic countries,
hill forts and beacon networks were important for warning against invasions. In Sweden and Finland, these beacons, known as
vårdkasar or
bötar, formed an extensive coastal warning system from the Late Iron Age and through the Middle Ages. Beacons were strategically placed on high ground for visibility, constructed from
tar-rich wood to ensure bright flames. They were mentioned in medieval laws like
Upplandslagen and described by Swedish writer
Olaus Magnus in 1555 as tools for mobilising armed defenders during crises. In
Wales, the
Brecon Beacons were named for beacons used to warn of approaching English raiders. In England, the most famous examples are the beacons used in
Elizabethan England to warn of the approaching
Spanish Armada. Many hills in England were named Beacon Hill (or Beacon
Fell) after such beacons, including
Beacon Fell, Cumbria and
Beacon Fell, Lancashire. In England the authority to erect beacons originally lay with the King and later was delegated to the
Lord High Admiral. The money due for the maintenance of beacons was called
Beaconagium and was levied by the sheriff of each county. In the
Scottish borders country, a system of beacon fires was at one time established to warn of incursions by the English.
Hume and Eggerstone castles and Soltra Edge were part of this network. In Spain, the border of
Granada in the territory of the
Crown of Castile had a complex beacon network to warn against Moorish raiders and military campaigns. Due to the progressive advance of the borders throughout the process of the Reconquista, the entire Spanish geography is full of defensive lines of castles, towers and fortifications, visually connected to each other, which served as fortified beacons. Some examples are the Route of the Vinalopó castles or the distribution of the castles in Jaén.
Ceremonial use in June 2022. In later centuries, advancements in technology, such as the
telegraph, rendered beacon systems obsolete for rapid communication. The use of such beacons transitioned from practical communication to symbolic and ceremonial roles, where the lighting of beacons was repurposed to mark significant national events. Beacons were lit across the United Kingdom to celebrate Queen Victoria's
Diamond Jubilee in 1897, Queen Elizabeth II's
Platinum Jubilee in 2022, and to commemorate events such as the 70th anniversary of
VE Day, and the 80th anniversary of the
D-Day landings in 2024. ==Military use (20th–21st century)==