Why Was the Lighthouse of Alexandria Built?

Instructor: Brittney Clere

Brittney, a National Board Certified Teacher, has taught social studies at the middle school level for 15 years.

Lighthouses are used today to help mariners make their way at sea. But how did these structures come about? In this lesson, we will look at what motivated the construction of the first lighthouse and the legacy it created.


In 332 BCE, Alexander the Great defeated the Persians and took the city of Memphis, which was the capital city of Egypt at the time. The Egyptians accepted him as their new pharaoh. After exploring his new territory, Alexander decided to turn the small fishing village of Rhacotis into his new capital city. The village was ideal because it sat on the coast, and Alexander wanted access to the sea so merchant ships could bring goods in and out of the city.

In an obvious move, Alexander named his capital city Alexandria. Like the rest of Egypt, the coastline is very straight and does not have mountains that could be used as lookout points. Shallow spots and reefs also dot the area. This made it difficult for ships to navigate into the harbor, especially at night.

Sculpture of Ptolemy Soter I.
Ptolemy I

After the death of Alexander the Great, Ptolemy Soter I took control of the realm. He faced the same problems when it came to ships trying to access the city. Unlike his predecessor, however, he came up with a solution. Ptolemy had his friend, Sostratus of Cnidus, design and build the very first lighthouse. The Lighthouse of Alexandria, which is also called the Pharos of Alexandria, was built on the tiny island of Pharos directly in front of the city of Alexandria.

The Lighthouse of Alexandria.
Lighthouse of Alexandria

The lighthouse stood approximately 450 feet tall and was built with light-colored stone and molten lead to create walls strong enough to withstand the crashing waves. The first level was squared shape, the middle level had an octagon shaped, and the top was circular. A reflective mirror on the top level would reflect the sunlight during the day to guide the ships. A fire was used at night. Some sources say it was so effective, it could be seen from 100 miles out to sea.

There are a few legends that claim the lighthouse was also used to set fire to incoming enemy ships. Recent experiments have shown that the mirror and light may have had the capacity to create such a blaze, but most scholars have not accepted the story as true due to the limited technology at the time.

Some sources say that a statue in honor of Poseidon, the god of the sea, was on the very top of the lighthouse. Other descriptions, however, claim that the statue was either Alexander the Great or Ptolemy I. If these recordings are true, the statue would have served as notice of who was in control to anyone entering the city by sea.

The lighthouse was an expensive endeavor. In the currency used at that time, it cost around 800 'talents'. Today, that would equal approximately 3 million dollars.

Ptolemy Soter I died before it was finished, so it was his son, Ptolemy Philadelphus, who had the honor of inaugurating the lighthouse. There are some conflicting ideas on when exactly this occurred, but it was in either 283 BC or 279 BC. Either way, the lighthouse guided thousands of ships safely into harbor until it was eventually destroyed by two earthquakes in 1303 and 1323 BC.

Ancient mosaic of the Lighthouse of Alexandria.

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