Lighthouse of Alexandria

The Lighthouse of Alexandria stood on the island of Pharos in the harbour of Alexandria, built on the orders of the early Ptolemaic kings around 280 BCE. It ranked among the tallest man-made structures on earth for most of its history, and it served Alexandria for almost 1500 years before earthquakes brought it down in the 14th century CE. Its remains were later identified in the eastern harbour by French underwater excavations.

Construction of the Lighthouse of Alexandria began in 297 BCE, when Ptolemy I Soter ordered the work to proceed. The Souda lexicon gives that same date for the start of building, and records that the tower was completed under Ptolemy II in the 124th Olympiad. The project rose in record time, taking only about fifteen years to stand at the harbour entrance as a landmark visible from afar.

Pliny the Elder reported that the construction cost 800 talents, equivalent to about 17 tons of silver. He further affirmed that the cost of erecting the Pharos was equal, at the present value, to about 390,000 pounds.

The tower rose in three stages: a square lowest section, an octagonal middle section, and a cylindrical top, each sloping slightly inward. Most sources agree that it was white. Its height exceeded 350 feet (110 metres), and a broad spiral ramp led to the fire burning at night on the summit.

Inside, the Pharos was ascended by a staircase as broad as those ordinarily erected in towers, terminating about half-way, above which the building became much narrower. From the gallery the ascent continued by a flight of steps much narrower than the lower staircase and pierced with windows to give light to those making use of it.

A fire was kept at the top of the tower to make it visible at night, and it is likely that oil was burned because wood was scarce. The beacon warned ships of shoals and marked the harbour entrance as vessels moved at night. Josephus credits the fire with a visibility of about 300 stades, roughly 55 km. Strabo describes the tower as indicating the path to reach the coast, serving as a landmark at night, and pointing toward the ports while avoiding the main coastal dangers.

Pliny notes that similar beacons burned at Ostia and Ravenna and that an uninterrupted flame risked being mistaken for a star. The construction established a lasting architectural and functional model for maritime signaling structures. The common noun pharos, meaning a tower that guides sailors, appears in Greek only from the first century CE, and the term came to designate a maritime signaling device only from the end of the first century CE.

Greek and Latin texts designate the lighthouse by the word tower. It stood on the island of Pharos, joined to the mainland by a causeway named the Heptastade. Pharos is an oblong island lying close to the mainland, forming with it a harbour with two mouths. The Heptastadium served as a bridge and also as an aqueduct while Pharos was inhabited. Entering the Great Harbour, the island and tower lay on the right and the promontory Lochias with its royal palace on the other side.

Strabo describes a tower of white marble with many stories on the rocky tip of the island, bearing the island's name, an offering by Sostratus of Cnidus, a friend of the kings, for the safety of mariners. Pliny extols the towering structure on Pharos, the island commanding the harbour of Alexandria, and says Ptolemy allowed the architect Sostratus of Cnidus to inscribe his name on the building.

Lucian of Samosata called it the greatest and most beautiful of all works of architecture. Achilles Tatius likened the tower to a mountain set in the middle of the sea that touched the clouds. A medieval description praised it as singularly remarkable for height and massiveness and of exceeding utility, its fire burning night and day for the guidance of navigators.

Coins struck from the reign of Domitian to that of Commodus show a three-section tower topped by a statue and form the most important documentary evidence for its appearance. Writers from Julius Caesar to the Arab traveller el-Balawi described the illuminated tower, whose image also appears on coinage and mosaics.

The identity of the mind behind the Pharos has never been settled beyond dispute. Several ancient sources name the architect Sostratus of Cnidus as the builder of the lighthouse, though he may instead have been its financial backer. A competing reading of the evidence holds that Sostratus of Knidos most plausibly financed the tower rather than serving as its architect, and that he dedicated the monument as a friend of kings. The two positions are not easily reconciled, and the record leaves the question of authorship open.

Posidippus makes a watcher of Pharos, the savior of the Greeks, the true subject of his epigram and names him Zeus Saviour at the end.

One epigram by Posidippus tells sailors about to cross the sea to salute Arsinoe Euploia at the temple that the Samian admiral Callicrates, son of Boiskos, dedicated for them when he was nauarch. An omen epigram by the same poet wishes that the Thracian crane lead the halyards for those about to travel the Egyptian sea, as a favorable sign for the helmsman.

A number of twelfth-century Andalusian travellers, among them Ibn Jubair, Abu Hamid al-Gharnati and Ibn al-Shaikh al-Balawi, left remarkable accounts of the lighthouse.

Abu Hamid al-Gharnati described three tiers of hewn stone: a square lower stage on a platform, an octagonal middle stage and a round top.

Some accounts described the Pharos mirror as made of finely wrought glass or transparent stone, so that a man sitting under it could see ships at sea that were invisible to the naked eye.

The final section carried a wooden dome built by Ahmed Ibn Touloun, serving as the highest mosque in the Muslim world and as an observatory whose four doors faced the cardinal points.

Earthquakes in 796 and 950 and again in 1303 and 1323 badly damaged the lighthouse, yet records attest regular repairs and extensions. Al-Maqrizi records that Sultan Baybars restored one of the fallen corners in 1274 and reinstalled the mosque dome that the earthquake of 1303 later destroyed. Maqrizi reported that the earthquake destroyed the lighthouse completely, the restoration attempts begun in 1304 came to nothing, and the tower served as a quarry before sinking beneath the sea.

The Citadel of Qaitbay was built by Sultan al-Ashraf Abu al-Nasr Qaitbay between 1477 and 1479, raised directly over the ruins of the Alexandria lighthouse. Its purpose was defensive: it served as Alexandria's protection against naval attacks. The structure was built of limestone and covered an area of roughly 17550 square metres.

The main tower occupies the northwest of the courtyard and takes the form of a massive three-floored square fort. Half-circular corner towers carry balconies for defence.

Analysis of the submerged site led to the identification of the ruins of three different structures: the lighthouse in the north-western part, a Roman-era structure in the north-east and a seawall built of re-cut granite columns. The largest fragments recovered include colossal statues and blocks weighing up to 40 tonnes.

Since 1994 the CEAlex has carried out one or two excavation campaigns per year, with each campaign's duration depending on the weather and the state of the sea. Since 2012 the CEAlex has run a major photogrammetry programme to digitise the site's surface, and by January 2020 the digital surface model covered roughly 10,250 square metres, around 65 per cent of the site, with 3040 blocks recorded in the database.

A bronze signet ring engraved with an image of the Lighthouse of Alexandria was recovered from the submerged island of Antirhodos in Alexandria's Eastern Harbor by a team from Egypt's Supreme Council of Antiquities and the European Institute for Underwater Archaeology.

After the pyramids of Giza, the lighthouse stood as the tallest structure built by human hands. It may have influenced later Arab minaret architecture, and it inspired copycat towers in harbours around the Mediterranean. The lighthouse of Taposiris Magna, about thirty meters tall, is considered a smaller-scale replica.

The UN cultural agency announced it would help Egypt build an innovative underwater museum in the Bay of Alexandria on a site of archaeological remains thousands of years old. The planned museum would be partly above water and partly submerged, allowing visitors to see archaeological artefacts lying on the seabed.

The Convention on the Protection of the Underwater Cultural Heritage was adopted on 2 November 2001 at UNESCO's 31st General Conference and urges states to take all appropriate measures to protect underwater heritage. The 2001 Convention provides a common legally binding framework for states on how to identify, research and protect their underwater heritage while ensuring its preservation and sustainability.

• around 280 BCE
  Construction
  The Pharos was built on the orders of the early Ptolemaic kings.^{1Great Wonders: The Lighthouse at Alexandria: The Pharos in the Land of the Pharaoh · Penn Museum, University of Pennsylvania ↗}
• 1477
  Qaitbay's tower
  Ibn Iyas reports that Sultan Ashraf Qaitbay ordered a tower built on the old foundations of the lighthouse.^{11The Lighthouse of Alexandria in Medieval Arabic Texts · Centre d'Etudes Alexandrines (CEAlex), Pharos Project ↗}
• 2012
  Photogrammetry programme
  The CEAlex began a major photogrammetry programme to digitise the site's surface.^{13Underwater Excavations at the Lighthouse Site · Centre d'Etudes Alexandrines (CEAlex), Pharos Project ↗}
• January 2020
  Digital surface model
  The digital surface model covered roughly 10,250 square metres, around 65 per cent of the site, with 3040 blocks recorded in the database.^{13Underwater Excavations at the Lighthouse Site · Centre d'Etudes Alexandrines (CEAlex), Pharos Project ↗}