Completed Project

Hagia Sophia

Istanbul, Turkey
Did You Know?
Justinian I, one of the earliest Byzantine rulers, ordered the architects Anthemius of Tralles and Isidorus of Miletus to design Hagia Sophia in the heart of what was then Constantinople.
A Closer Look

Hagia Sophia


Justinian I, one of the earliest Byzantine rulers, ordered the architects Anthemius of Tralles and Isidorus of Miletus to design Hagia Sophia in the heart of what was then Constantinople. Justinian was a prolific builder, and during his long reign from A.D. 527 to 565 he commissioned several hundred religious spaces and public structures across Europe. Hagia Sophia, Greek for “Divine Wisdom,” replaced an earlier basilica with the same name; the second church, built from A.D. 532-537, was by far the Emperor’s most ambitious architectural project. The central dome of the cathedral measures 107 ft across and hovers 180 ft above the floor, encircled by 40 arched windows. Justinian himself acted as the dome’s conservator when he had it restored in A.D. 563 after fire and earthquakes damaged the building. In its original form, Hagia Sophia had no figural mosaics, perhaps due to prevailing notions of iconoclasm at the time. From the 9th-14th centuries, however, successive generations of Byzantine monarchs filled the curving walls with imperial portraits and religious iconography. For nearly a millennium, the church functioned as the hub of Eastern Christianity and the location of the Orthodox Patriarch, the counterpart to the Pope in Rome. Hagia Sophia was transformed into a mosque after the fall of the city to the Ottoman invaders in 1453. Hagia Sophia became a secular museum following the creation of the Republic of Turkey in the early 20th century.

How We Helped

World Monuments Fund placed Hagia Sophia on its inaugural Watch list in 1996 and then included in again in 1998 in response to a number of threats facing this Byzantine gem. The cathedral’s copper roof had cracked, causing water to leak down over the fragile frescoes and mosaics. Moisture entered from below as well: rising ground water had raised the level of humidity within the monument, creating an unstable environment for stone and paint. WMF secured a series of grants from 1997 to 2002 for the restoration of Hagia Sophia’s famous dome and funds were matched by the Turkish government. The first stage of work involved the structural stabilization and repair of the cracked roof, which was undertaken with the participation of the Turkish Ministry of Culture and the Conservation Laboratory in Istanbul. The second phase, the preservation of the dome’s interior, afforded the opportunity to employ and train young Turkish conservators in the care of mosaics. By 2006, the WMF project was complete, though other areas of Hagia Sophia continue to require conservation.

Why It Matters

Hagia Sophia, the finest architectural product of Emperor Justinian’s reign, was an engineering marvel at the time of its completion in A.D. 537. Not until the 15th century would another building be erected that was capable of housing as much area under one roof. In addition to its structural accomplishments, the cathedral was also spectacularly adorned with silver, red porphyry, green marble, and millions of golden tesserae, which were carefully inlaid at angles to reflect the light. Byzantine figural mosaics and frescoes were commissioned over a period of four centuries by the rulers of Constantinople; these images visually document the progression of art and religious life in the Eastern Roman Empire. Today, Hagia Sophia still testifies to the tangled and interconnected histories of Rome, Byzantium, medieval Christianity, and the Ottomans. As a museum, the monument remains an essential part of the modern city, an urban landmark located within the UNESCO World Heritage Site of Historic Istanbul.

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