Lighthouse of Alexandria

Lighthouse of Alexandria is a monumental sea lighthouse constructed in the 3rd century BCE on the island of Pharos off the coast of Alexandria, Egypt, and recognized as one of the Seven Wonders of the Ancient World. It is regarded as one of the earliest examples of lighthouse construction and remained standing for over a millennium until the 14th century on the site where the Citadel of Qaitbay now stands. Also known as the Pharos Lighthouse, it was built on Pharos, a small, rectangular island located along the western shore of the Nile Delta where its western branch empties into the Mediterranean Sea.

Colored Engraving of the Lighthouse of Alexandria (Wellcome Collection)

History and Construction Process

Alexandria, founded in 332 BCE by Alexander the Great (III of Macedon), quickly became the capital of his empire and of Egypt. After Alexander’s death, his empire was divided among his generals, and Egypt fell to Ptolemy I Soter.

The idea of constructing a lighthouse was first conceived by Ptolemy I Soter to warn ships of dangerous reefs at sea. However, Soter died before the massive construction could be completed, leaving the task to his son, Ptolemy II Philadelphus. Construction began in 285 BCE and was completed in 247 BCE. According to tradition, the tower, built of white marble, cost 800 talents (an ancient unit of weight), an amount equivalent to more than 20 tons of precious metal.^【1】

The construction process faced challenging architectural and geographical conditions. Pharos Island was directly exposed to open-sea waves. Consequently, the foundation was excavated down to the seabed for reinforcement, and the lower sections were strengthened with sloping stone blocks above sea level. The stones used in the lighthouse’s construction were sourced from quarries west of Alexandria: white calcareous stone, marble, and Aswan granite. To eliminate gaps between stone blocks and enhance resistance to seawater, the molten lead joining technique was employed.

In the initial phase of construction, a breakwater was built using large stone masses to stabilize the seabed, upon which the walls of the square-plan ground floor were erected. The blocks used in the ground floor were carefully smoothed and fitted together interlockingly. As the widest and heaviest section of the lighthouse, this level served as the primary load-bearing structure. Subsequently, an octagonal middle section and a cylindrical upper section were constructed. During these stages, both stonemasonry and bronze casting techniques were combined, particularly in the lengthy process of shaping the ramp system leading up to the dome.

The lighting mechanism was installed during the final phase of construction. A large bronze cauldron was placed on the upper platform, filled with a mixture of wood and oil designed to burn continuously. To ensure visibility from great distances, parabolic bronze mirrors were positioned behind the cauldron. This allowed sunlight to be reflected during the day and the flame’s glow to be directed toward the sea at night.

After construction, regular maintenance and repairs were carried out by successive Egyptian rulers. During the Roman Empire, the lighting system atop the lighthouse was renewed and the bronze mirrors were repaired. After the Islamic conquests, the lighthouse continued to function for some time; during the reign of Ibn Tulun in the 9th century, a wooden dome and a small mosque were added to its upper section. In this period, the lighthouse also served as a minaret. However, increasing earthquakes from the 10th century onward weakened its structural integrity, and by the mid-14th century, most of the structure had collapsed.

The lighthouse suffered damage from numerous earthquakes beginning in 796 CE. Significant shocks occurred in 796, 956, 1303, 1334, 1341, 1348, and 1375, causing severe damage. The 956 earthquake caused the upper 25 meters to collapse, while the 1303 earthquake destroyed a large portion of the structure. Finally, a violent earthquake in 1375 completely demolished the lighthouse.

Ibn Battuta, during his visits to Alexandria in 1326 and 1349, observed the lighthouse in two different states. On his first visit, he saw the structure still standing; on his second, he found it in ruins and could not even approach its entrance.^【2】

Engraved Depiction of the Lighthouse of Alexandria (Lacma)

Architectural Features and Structure

The Lighthouse of Alexandria is considered one of the tallest structures of the ancient world, standing approximately 120 to 146 meters high. Its architect is known as Sostratus of Cnidus. Sostratus employed the engineering knowledge of his time to design a structure that was both aesthetically impressive and functionally effective. However, according to ancient convention, such monumental buildings were typically dedicated in the name of the ruler. Nevertheless, it is known that Sostratus secretly inscribed his own name on the entrance of the structure:

“Sostratus of Cnidus, son of Dexiphanes, to the two savior gods for the safety of seafarers.” ^【3】

The structure was situated at the eastern tip of Pharos Island, commanding a strategic position over the harbor and built to guide maritime traffic. Its base features a multi-tiered square-plan tower system composed of three main sections that narrow as they rise.

Sections

First Level (Ground Floor – Square Plan Mass)

With a base measuring approximately 30 by 30 meters, this level stands about 60 meters high. It contains around 300 rooms, used for housing workers, storing fuel (wood and oil), and operating mechanical systems. Ventilation openings and windows were incorporated to reduce the risk of collapse within the chambers.

At the top of this level stood four large bronze statues representing Triton (son of Poseidon). These figures are also depicted on Roman coins. Inside the ground floor was a large reservoir fed by a water pipeline from the city.

Second Level (Octagonal Middle Section)

This section is approximately 30 meters high. Its octagonal plan ensured balanced load distribution to the upper levels and provided aerodynamic resistance against wind pressure. Its facades were adorned with pilasters, niches, and small columns.

Third Level (Cylindrical Tower and Dome)

This section is approximately 15 meters high. It was crowned by a dome 8 meters tall, atop which stood a bronze statue of Poseidon, forming the highest point of the lighthouse.^【4】 This level housed the lighthouse’s light source. The fire emitted smoke during the day and a bright flame at night, visible for kilometers. It is also believed that a mechanical crane system was located here to facilitate the transport of wood and oil.

Access System and Internal Organization

The Lighthouse of Alexandria was designed with a ramp system instead of internal stairs. This ramp enabled people and animals—particularly donkeys and mules carrying supplies—to ascend to the top. The spiral inner wall along the ramp formed the structural skeleton of the lighthouse. Additionally, spiral staircases provided access to each level.

Iconographic and Architectural Influence

• During the Byzantine period, it served as a model for the development of belfries and watchtowers.
• It is regarded as one of the earliest inspirations for the minaret form in Islamic architecture. The lighthouse’s three-tiered composition is notably repeated in early North African minarets such as the Giralda (Seville), the Hasan (Rabat), and the Koutoubia (Marrakesh).^【5】

Historical Significance and Fate

The Lighthouse of Alexandria remained standing long after the eastern provinces of the Roman Empire adopted Christianity. Even during the Arab conquests in the 640s CE, it is recorded that the light from Pharos continued to guide Hellenistic ships. Over time, the lighthouse also served as a minaret; historical records note that Ahmad ibn Tulun climbed its wooden dome in 875 to perform the call to prayer.^【6】

Over the centuries, the foundation weakened. An earthquake on December 28, 955 or 956 caused the collapse of approximately 25 meters of the upper section. Although neglect began after the construction of Cairo from 969 onward, the remaining 60 to 70 meters of the lower structure were restored and repurposed in 1182, when a domed mosque was built upon it. Another major earthquake in 1375 led to the lighthouse’s final destruction.

In the 12th century (1165–1173), Benjamin of Tudela recorded that the lighthouse served as a navigational landmark for sailors, visible from 100 miles away during the day, with ships steering toward its flame at night. The discovery of the Cape of Good Hope in 1498 and the subsequent shift of shipping routes diminished Alexandria’s importance. Eventually, the remains of Pharos were either lost or reused as building material for other structures.

Its Role in Numismatics

The Lighthouse of Alexandria is one of the rare ancient structures whose image survives on extant Roman coins. Depictions of the lighthouse appear on coins minted from the reign of Emperor Domitian (81–96 CE) through that of Emperor Commodus (180–192 CE), approximately 300 years after its construction and 100 years after Rome’s takeover of Egypt.

Three distinct types of lighthouse imagery appear on the reverse of these coins: the first shows the lighthouse itself along with statues of Isis Pharia or Zeus Soter and Triton; the second features the figure of Isis Pharia, often depicted with a sail, occupying half the coin’s surface; the third replaces Isis with a ship. After Commodus, the lighthouse ceased to appear on coins.^【7】

• First Type Depiction: This type presents the lighthouse in its complete architectural form and is considered a significant visual source. The coins depict the lighthouse along with its prominent statues: Triton, son of the sea god Poseidon and herald of the sea, or Isis Pharia, the protective goddess of Alexandria, or Zeus Soter, the savior.

• Second Type Depiction: In this type, the architectural structure of the lighthouse is partially shown, with a large figure dominating the coin’s surface. This figure is typically Isis Pharia, depicted with a sail or standing on a ship.

• Third Type Depiction: The third type resembles the second composition but replaces the figure of Isis Pharia with a direct depiction of a ship.