The Citadel of Qaitbay guards the eastern harbor of Alexandria on the former island of Pharos. The ancient lighthouse that once stood nearby, one of the renowned wonders of the Mediterranean world, was repeatedly damaged by earthquakes and had largely collapsed by the later Middle Ages. Mamluk sultan al-Ashraf Qaitbay ordered a new coastal fortress there in 1477–1479 amid concern about Ottoman naval expansion. Builders reused some ancient stone from the lighthouse site, but the citadel is fundamentally a purpose-built fifteenth-century fortification, not the surviving Pharos converted intact.

The limestone complex included an outer defensive wall with towers, an inner enclosure, garrison spaces, stores, cisterns, and a massive square keep. Within the keep, vaulted rooms surrounded a central courtyard, and a mosque served the soldiers. Openings, passages, and roof positions supported surveillance and artillery adapted to late medieval warfare. Qaitbay invested heavily in Mediterranean defenses, and later Mamluk and Ottoman authorities repaired and rearmed the post. Alexandria's harbor geography gave the citadel symbolic importance even when changing weapons and regional power reduced the effectiveness of older masonry works.

The fortress remained in military use under Ottoman and Egyptian rulers. Muhammad Ali strengthened Alexandria's coastal defenses in the nineteenth century, but British naval bombardment during the Anglo-Egyptian War of 1882 badly damaged the citadel, especially the keep and upper structures. Abandonment and exposure to salt, wind, waves, and humidity compounded the losses. Twentieth-century Egyptian authorities undertook major restoration, rebuilding collapsed sections and returning the monument to a coherent architectural form. That intervention saved the landmark but means portions visible today are modern reconstructions based on surviving evidence.

Substantial Mamluk masonry, spatial organization, foundations, and reused ancient blocks survive alongside Ottoman alterations, nineteenth-century damage, and twentieth-century rebuilding. The keep's crisp walls and restored rooms should therefore not all be described as untouched fifteenth-century fabric. Conservation continues to address marine salts, water, structural movement, crowding, and the surrounding shoreline. Archaeology beneath Alexandria's waters has identified lighthouse-related blocks and sculptures, but assigning every reused stone in the citadel directly to the Pharos would exceed the evidence. The fortress and the ancient wonder occupy connected yet distinct historical layers.

Egypt's Ministry of Tourism and Antiquities administers Qaitbay Citadel as a protected monument and museum attraction. Access and individual interior routes depend on current conservation and visitor arrangements. Interpretation works best when it follows Alexandria beyond its classical fame into the Mamluk, Ottoman, and modern periods. The site embodies adaptation: a new Islamic fortress occupied a celebrated ancient location, later regimes modified it, bombardment shattered it, and restorers rebuilt significant portions. Its authenticity rests on the legible combination of original masonry, reused material, repaired fabric, and accurately acknowledged reconstruction rather than a simple claim that the Lighthouse survives above ground.