The Hagia Sophia (Church of the Holy Wisdom of God, or the Logos, or the Second Person of the Holy Trinity) stands close to the Blue Mosque and together the two represent the two great religions of Istanbul: Christianity and Islam. The Hagia Sophia dates from the time of the Roman Emperor Constantine (360 AD), was turned into a mosque in 1453, and then, in 1931, a museum. It stood for over a thousand years therefore as a Christian Church, more specifically a Cathedral of the Eastern Orthodox Christian Church, famous for its interior Byzantine art and its architecture. Even now one is struck by the contrast between the frank humanity of the interior art, mosaics mostly, and the colorful abstractions of the interior of the Blue Mosque.
An Ottoman mosque from the 15th to the 20th century, the Hagia Sophia was converted into a museum in 1931 by Ataturk, the President of the secular Republic of Turkey. It stands now simultaneously as a moving reminder of the earlier stages of institutionalized Christianity and a popular tourist attraction.