Hagia Sophia, in Istanbul Turkey, is a former patriarchal basilica; it was later a mosque and is now a museum as well as World Heritage Site. It occupies a prominent place in the history of art and architecture, as one of the greatest surviving examples of Byzantine architecture. It was the largest cathedral in the world for more than 1000 years, until the completion of the Seville Cathedral in 1575. Its architectural and liturgical influence was widespread in the Eastern Orthodox, Roman Catholic and Muslim worlds alike.

Although it is sometimes referred to as Saint Sophia, its Greek name is "Church of the Holy Wisdom of God". The basilica was not dedicated to a saint named Sophia, but to Divine Wisdom.

Some say that the site was first a pagan temple in honor of Apollo and Venus.

Later, three separate basilicas – all named Hagia Sophia – were erected here at different times. The first two were destroyed during riots. The Byzantine Emperor Justinian constructed the cur-rent building – between 532 and 537 – as a church. It was the seat of the Patriarchate of Constantinople and the religious cen-ter of the Orthodox Byzantine Empire for nearly 1000 years.

Many consider Hagia Sophia the supreme masterpiece of Byzantine architecture because of the innovative construction of its dome. The central structure, 102 feet in diameter and 184 feet high, spans the spacious nave. The dome sits on supporting arches (pendentives) that allow the round dome to flow gracefully into the square shape below. The arches at the east and west are extended and buttressed by great half-domes. These half domes rest on smaller semi-domed porticos. A corona of 40 arched windows encircles the central dome, allowing copious sunlight into its interior and creating the impression that the Hagia Sophia is a perfect golden shell. The innovative design of the dome and its windows establish this structure as one of the most advanced and ambitious monuments of late antiquity and make it a magnet for art historians and architects.

Since 1993, cleaning, roofing and restoration have been underway. Recent visitors, including myself, have found our view of the dome obstructed by huge scaffolding stretching up into the dome in the center of the nave.

One can still feel the openness of the building in the upper galleries, which are wide, light and airy. They can be reached by climbing a winding cobblestone ramp to the second floor. Among the masterpieces preserved there are the Comnenos and the Empress Zoe Mosaics.

Originally, the interior decorations consisted of abstract designs on marble slabs on the floor and mosaics on the curving vaults. One can still see mosa-ics of the two archangels Gabriel and Michael. Most of the images, however, were destroyed during the iconoclast con-troversy (726-843). This dispute divided early medievel Christianity between those who saw veneration of images of God, Jesus Christ and the saints as idolatry and those who treasured them as a rich spiri-tual resource. The remaining mosaics are from the post-iconoclast period. Apart from the these, a large number of figura-tive decorations were added during the ninth century: among them an image of Christ (in the central dome), Orthodox saints, prophets and Church fathers in the space below and scenes from the gos-pels in the galleries.

In 1453, the Ottoman Turks con-quered Constantinople and Sultan Mehmet II ordered the building con-verted into a mosque. The bells, altar, and sacrificial vessels were removed and many of the mosaics were plastered over. Islamic features, such as the mihrab (a niche set into the middle of a wall in order to indicate the direction of Mecca), the minbar (a raised pulpit reached by a set of steps) and the four minarets outside were added over the course of the Ottoman Empire. In the nineteenth century, master calligraphers inscribed huge leather medallions with the name of Allah and the names of the prophet Muhammad, his grandchildren and the first four Muslim caliphs. These were suspended high on the columns supporting the dome.

For almost 500 years, Hagia Sophia, as the principal mosque of Istanbul, served as a model for many later Ottoman mosques including the famous Sehzae, Suleymaniye and Rustem Pasha Mosques.

Hagia Sophia remained a mosque until 1935, when the secular Republic of Turkey under Mustafa Kemal Ataturk ordered it converted into a museum.

To appreciate Hagia Sophia fully, one should try to look at it not just as a museum, but as the magnificent and mys-tical church and mosque it once was. This can be difficult because of the large number of visitors thronging around their guides. In addition, the ongoing renova-tions are difficult to ignore, especially the scaffolding under the dome. It cuts the amount of light that enters the space from the windows above, and makes the interior quite dim. The mystical light described by earlier visitors is difficult to imagine. One hopes that when the resto-ration of the dome is completed light will again flood the space.

The huge Islamic disks suspended from the main dome since the 19th century remain in place and make a fascinating religious contrast with the uncovered Christian mosaics. However, some will find them rather overpowering and out of place in a building that was built as a Christian cathedral and whose architecture is based on Christian spiritual symbolism. In the same way the minbar and mihrab can seem jarring, located as they are adja-cent to the space where the Christian altar once stood.

However, we should thank Sultan Mehmet for his attempt to convert the basilica into a mosque. Not only was it a step forward in religious relations but he also preserved an architectural masterpiece. He plastered over the mosaics and frescos, and added Islamic elements such as the minarets, minbar, and mihrab rather than destroying the building and decorations. In the past rival Christian groups had either destroyed the church or looted it.

In 1935, when Ataturk trans-formed the building into a museum, he sidestepped controversies over the continuing religious use of the building. The carpets were removed and the marble floor decorations appeared for the first time in centuries. Expert restorers removed the white plaster covering the mosaics.

In spite of the good inten-tions of both Sultan Mehmet II and Mustafa Kemal Ataturk, the visitor may find Hagia Sophia an uneasy mix of Christian and Islamic symbols. Of course, this is due to its long history as both a church and a mosque. Thus, a particular challenge arises in the restoration process. Christian iconographic mosaics are being gradually uncovered. In the pro-cess, important, historic Islamic art may be destroyed. Restorers have attempted to maintain a bal-ance between the two cultures. For example, much controversy surrounds the issue of whether the Islamic calligraphy on the dome of the cathedral should be removed in order to permit the underlying mosaic as Christ as Master of the World to be exhibited (assuming the mosaic is still restorable).

In its own way, Hagia Sophia continues as a symbol of the meeting of Christianity, Islam and secularism. First it was a Christian church, and then it was a Muslim mosque. Now, as a museum, it is trying to balance the two.

Cetta Kenney is Photo Editor of Interreligious Insight. She serves as a Trustee of two of the journal's co-publishers, Common Ground and the Interreligious Engagement Project. She has long been active in global interreligious work, with IEP21, the Parliament of the World's Religions, and the International Interreligious Peace Council – which she has also served as official photographer. All photos in this article were taken by the author.