Fire on the high ground
The earliest coastal lights were not always meant for ships. Fires of wood, and later coal, were lit on headlands, hilltops and church towers to warn, to signal and to mark a harbour mouth. The English word "beacon" descends from the Old English bēacen, meaning a sign or signal, and for centuries it covered all of these uses at once.
In England, chains of hilltop beacons were kept ready for news of invasion. In the summer of 1588 they carried word of the Spanish Armada along the south coast and inland. These were communication networks rather than navigation aids, but they established a habit of keeping fires laid and watched, which the later lights inherited.
The ancient towers
The first great purpose-built light was the Pharos of Alexandria, raised under the Ptolemies around 280 BC on the island from which it took its name. Ancient writers describe a tower of exceptional height, and it gave the world the word pharology, the study of lighthouses, as well as the French phare and Italian faro. Earthquakes ruined it over the medieval centuries; the Citadel of Qaitbay now stands on its site.
Rome carried the idea across its empire. The Tower of Hercules at A Coruña in northern Spain dates from the first or second century AD, was refaced in the eighteenth century, and still shows a light today; it was inscribed as a UNESCO World Heritage Site in 2009. At Dover, the Roman pharos survives within the castle grounds beside the church of St Mary in Castro.
Medieval lights and chantries
After Rome, light-keeping often fell to religious houses. Monks and chantry priests tended lamps as an act of charity towards sailors. St Catherine's Oratory on the Isle of Wight, built in 1328 and known locally as the Pepperpot, is a surviving example. On the Hook peninsula in County Wexford, Hook Head lighthouse incorporates a tower of the early thirteenth century and is counted among the oldest operating lighthouses in the world.
Charters and light dues
In 1514 Henry VIII granted a charter to the guild that became Trinity House. Through the seventeenth and eighteenth centuries, however, many English lights were private ventures, built under patent and paid for by light dues collected from ships in port. Scotland took a public route earlier: the Commissioners of Northern Lighthouses, today's Northern Lighthouse Board, were created in 1786 and lit their first light at Kinnaird Head in 1787. The Commissioners of Irish Lights took that name in 1867.
Eddystone: four attempts on one reef
The Eddystone rocks, some fourteen miles off Plymouth, became the proving ground of lighthouse engineering. Henry Winstanley's timber tower was lit in 1698 and swept away in the Great Storm of 1703, with Winstanley inside. John Rudyerd's timber-clad tower followed in 1709 and burned in 1755. John Smeaton's tower of 1759 used interlocking, dovetailed granite blocks and a hydraulic lime that set under water, a method that shaped rock lighthouses for the next century. When the rock beneath it eroded, James Douglass built the present tower in 1882, and the upper part of Smeaton's was rebuilt on Plymouth Hoe.
The Stevensons and the rock lights
In Scotland, Robert Stevenson, working with John Rennie, completed the Bell Rock lighthouse off Arbroath, first lit in 1811. It is the oldest surviving sea-washed lighthouse. His son Alan Stevenson built Skerryvore, finished in 1844, and later generations of the family designed lights across Scotland and beyond. The novelist Robert Louis Stevenson was Robert's grandson, and was expected for a time to follow the family trade.
From keepers to automation
The twentieth century brought electric light, radio beacons and, finally, automation. The last resident keepers in the United Kingdom left North Foreland in Kent in 1998. Satellite navigation now does most of the work, yet lights remain in service as a check against failure, guided internationally by IALA, the body that coordinates marine aids to navigation.