What Destroyed the Lighthouse of Alexandria?

For centuries, the Lighthouse of Alexandria guided mariners to the bustling Mediterranean port and capital of Ptolemaic Egypt—a beacon of human ingenuity and a symbol of the ambition of the Hellenistic age. The Lighthouse, also known as the Pharos of Alexandria, was named after the tiny island at the harbor's mouth where it was built. Ancient Greek writers hailed it as one of the Seven Wonders of the World, and it stood from the early third century B.C. until medieval times. But it stands no longer.

So, what destroyed the Lighthouse of Alexandria? "The ravages of time—but the chief agents of its eventual destruction were three significant earthquakes that destabilized it between 956 and 1303," says University of Cambridge classicist Paul Cartledge. The first two quakes badly damaged the lighthouse, and the third left it in ruins. Cartledge adds that it wouldn't be equaled for centuries: "Its function of throwing light far out to sea at night would never have been entirely superseded in the Age of Sail."

The Lighthouse of Alexandria was constructed on the orders of the Ptolemaic dynasty of Egyptian pharaohs to glorify the new city, which had been established by and named after the Macedonian king Alexander the Great. Ptolemy I had been a friend and general of Alexander, who seized Egypt from the Persian Empire in 332 B.C. After Alexander's unexpected death at Babylon in 323 B.C., Ptolemy (also a Macedonian) became the Egyptian pharaoh Ptolemy I Soter (Greek for "savior").

The Ptolemaic dynasty lasted 275 years—the longest of any Egyptian dynasty. They adopted Egyptian rites of kingship (including royal marriages between brothers and sisters) and were well received by the Egyptian people, who had bridled under their Persian predecessors. But their rule—and Egypt's independence—came to an end in 30 B.C., after the Egyptian queen Cleopatra VII (herself a Ptolemy) and her husband, the Roman rebellion leader Mark Antony, were defeated by Octavian (later Emperor Augustus) in a decisive naval battle at Actium.

Some sources state Ptolemy I ordered the lighthouse built, and it was completed in the 280s B.C. by his son, Ptolemy II Philadelphus (Greek for "sibling-loving," a reference to his marriage to his sister Arsinoe I). Cartledge says the lighthouse was mostly blocks of limestone and granite. Reconstructions show a tower in three parts, tiered like a wedding cake—a circular top above an octagonal middle section and a square base. The Lighthouse stood roughly 300 feet tall, with a bronze statue of the Greek sun god Helios on its summit. It was renowned as one of the tallest structures in the ancient world.

Unlike earlier capitals of ancient Egypt, Alexandria was located on the Mediterranean coast, and the Ptolemies encouraged trade with other places. But the approach by sea was beset by hidden shoals and other hazards. The lighthouse helped ships navigate safely to the city, which soon became one of the wealthiest in antiquity. "Part of the reason for building [the lighthouse] was competitive conspicuous display," Cartledge says. "But if it hadn't performed any other useful function, it would have been abandoned much sooner."

Scholars still dispute how the lighthouse produced light. The 10th-century Arabic writer al-Masudi (Ali ibn al-Husayn ibn Ali al-Masudi) wrote that the lighthouse used a mirror to reflect a burning fire and the rays of the sun. But scholar Andrew Chugg, author of the 2024 book, The Pharos Lighthouse in Alexandria, thinks al-Masudi was confused. Instead, Chugg says, the light seems to have been created by an oil lamp inside a transparent shell-like sphere, several feet across, which was open at the top so it functioned like a hurricane lantern, making the light brighter.

Ancient drawings of the Helios statue atop the lighthouse show it holding a spherical light, and it was described as a "second sun," Chugg says. Although no such sphere remains, Chugg thinks it would have been made from glass—Alexandria was a center for glass manufacturing—and that it was sometimes taken down for cleaning. The oil for the lamp may have been fed through the statue's outstretched arm, he says, and the smoke from the lamp may have guided ships during the day.

The Mediterranean is prone to earthquakes, so it is a wonder of ancient engineering that the Lighthouse of Alexandria stood for so long. Chugg likens it to the Colossus of Rhodes, a gigantic bronze statue built around the same time that also represented the god Helios, but on a smaller scale—it was about 100 feet tall, or roughly a third the height of the lighthouse.

The Colossus of Rhodes, however, stood for less than 60 years before it was toppled by an earthquake. The Lighthouse of Alexandria, by contrast, stood for more than 100 years until it was abandoned in the 12th century. A fortress built by a 15th-century Mamluk ruler of Egypt now stands at the site.

The remains of the lighthouse were found in the 20th century in the waters beside the site, and archaeologists recently recovered many of its giant stone blocks. The blocks will be studied and the data used to create a digital twin of the ancient structure, which the researchers hope will reveal more about how it was built and how it functioned.