In Byzantine Constantinople, nowadays called Istanbul, the emperor Justinian I commissioned a grand new building on this day in 532. Following a series of protests against him and his wife, the empress Theodora, Justinian sought to appease the citizens who had only weeks before burned down the church that he wanted to replace. He ordered the construction of a church so magnificent that it would be the center of Byzantine religion, which at the time had not yet been separated from the Roman Church. Construction began immediately, and in 537, after five years of construction, the Hagia Sophia was completed. A feat of architectural wonder, its name comes from the Greek word for Holy Wisdom, which become Hagia Sophia. It is considered to be the best of Byzantine architecture, and was the center for Byzantine theology. Eventually, when Constantinople was overrun by the Ottomans, it was turned into a mosque, which is how it remained until 1935. By that time, the Ottomans had fallen, and had been replaced with the Turkish Republic. They secularized the mosque, and converted it to a museum, which is now the second-most visited museum in Turkey.