The history of lighthouses refers to the development of the use of towers, buildings, or other types of structure, as an aid to navigation for maritime pilots at sea or on inland waterways.
Premodern era
Before the development of clearly defined ports, mariners were guided by fires built on hilltops. Since raising the fire would improve the visibility, placing the fire on a platform became a practice that led to the development of the lighthouse. In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for reefs and promontories, unlike many modern lighthouses. Excavation at Kuntasi on the coast of what is now India has revealed a square watch tower with a ramp which would have originally been 10–12 meters, used to guide boats coming to Kuntasi from Rann of Kutch. The possibility of it being a lighthouse cannot be ruled out. If so, the lighthouse would date from about 2000 BCE.
Greek-Roman period
According to Homeric legend, Palamedes of Nafplio invented the first lighthouse, although they are certainly attested with the Lighthouse of Alexandria (designed and constructed by Sostratus of Cnidus) and the Colossus of Rhodes. However, Themistocles had earlier established a lighthouse at the harbour of Piraeus connected to Athens in the 5th century BC, essentially a small stone column with a fire beacon.
Lesches, a Greek poet (c. 660 BC) mentions a lighthouse at Sigeion in the Troad. This appears to have been the first light regularly maintained for the guidance of mariners.
Written descriptions and drawings of the Pharos of Alexandria provide information about lighthouses, but the tower itself collapsed during an earthquake many centuries after its construction in the 3rd century BC by the Greeks. The Tower of Hercules at A Coruña in Spain has a Roman core, and the ruins of the Dover lighthouse in England give insight into construction; other evidence about lighthouses exists in depictions on coins and mosaics, of which many represent the lighthouse at Ostia. Coins from Alexandria, Ostia, and Laodicea in Syria also exist.
While the evidence provides insight into the exterior structure of these structures, there are many gaps in evidence concerning less visible aspects of the structures. The remains at A Coruña and Dover help determine how each lighthouse structure functioned, though one must make some assumptions to determine how the structures beacons were illuminated. Presumably locally available fuels will have included wood and probably coal to keep a fire going continuously during the night, and there is a large chimney leading to the top room at the Tower of Hercules. The example from Dover has been converted at some stage into a simple bell tower for the adjoining church.
Lighthouse keepers may have added combustible liquids to reduce the expenditure on fuel and keep the light steady during gales, but little information exists in the literature from the time. It may also be possible that the light was protected from the wind by glass windows, and large mirrors may have assisted in projecting the light beam as far as possible. It is likely that lighthouses would have required considerable labour for transporting the fuel and maintaining the flame. At Cape Hatteras in the 1870s, one keeper and two assistants kept themselves busy by tending more sophisticated flames from powerful oil lamps.
While artistic representations assist us in re-creating a visual image of lighthouses, they present many problems. Depictions of lighthouses on Roman coins, inscriptions, carvings, and mosaics present an inconsistent view of the actual appearances of the structures. Most show a building with two or three stories that decreases in width as it ascends. The limited size of coins could cause the producer of the coin to alter the image to fit on the surface. The similarity in depictions of lighthouses is symbolic rather than accurate representations of specific beacons.
Europe
During the European Middle Ages, many Roman lighthouses fell into disuse. Some did remain functional, such as the Farum Brigantium, now known as the Tower of Hercules, in A Coruña, Spain, and others in the Mediterranean Sea such as the Lanterna at Genoa. As navigation improved, lighthouses gradually expanded into Western and Northern Europe. One of the oldest working lighthouses in Europe is Hook Lighthouse located at Hook Head in County Wexford, Ireland. It was built during the Middle Ages, in a sturdy –circular design.