The Bulgarians of the Ottoman Empire used to pray at the churches of the PhanarOrthodox Patriarchy, but nationalistic movements allowed Bulgarians a national church in the 19th century, the Bulgarian Exarchate. The richly ornamented church is a three-domed cross-shaped basilica. The altar faces the Golden Horn and a 40 m-high belfry, the six bells of which were cast in Yaroslavl, rises above the narthex. Initially, a small wooden church was erected on the shore of the Golden Horn between Balat and Fener squares, where the current church is located. A house was donated by the statesman Stefan Bogoridi, and it was reorganized as a wooden church. It was inaugurated on 9 October 1849 and became an important site of the Bulgarian National Revival. The Ottomanroyal decree of 28 February 1870 establishing the Bulgarian Exarchate was first read inthe church. After the original wooden structure suffered from a fire, the larger current building was constructed at its place. An iron frame was preferred to concrete reinforcement because of the weak ground conditions. The construction plans were prepared by the Istanbul-based Ottoman ArmenianarchitectHovsep Aznavur. An international competition was conducted to produce the prefabricated cast iron parts of the church, won by an Austrian company, . The prefabricated elements, weighing 500 tons, were produced in Vienna in 1893 to 1896 and transported to Istanbul by ship through the Danube and the Black Sea. After one-and-a-half years, the church was completed in 1898 and inaugurated by Exarch Joseph on 8 September that year. The main skeleton of the church was made of steel and covered by metal boards. All the pieces were attached together with nuts, bolts, rivets or welding. In terms of architecture, the church combines Neo-Gothic and Neo-Baroque influences. St. Stephen was the product of 19th-century experimentation with prefabricated iron churches. The British, who invented the corrugated iron in 1829, manufactured portable iron churches to send to far-flung colonies like Australia. The Eiffel Tower's creator, French engineer Gustave Eiffel, designed iron churches that were sent as far as the Philippines and Peru. Now, St Stephen is one of the world's few surviving prefabricated cast iron churches. On December 27, 2010, St Stephen's feast day, a celebratory mass was held at the church in honor of its patron saint. Attending were the Vratsa Metropolitan Kalinik, bishop Naum, Chief Secretary of the Bulgarian Holy Synod, and representatives of the "St. Stephen Church" Foundation. Honoring the celebration the dome of the church was gold-plated using funds donated by the Bulgarians of Plovdiv. The church building underwent a renovation, which started under the Bulgarian-Turkish cooperation in 2011 and cost more than 15 million. On January 8, 2018, Turkish PresidentRecep Tayyip Erdogan and Bulgarian Prime MinisterBoyko Borisov were present at the inauguration of the renovated St. Stephen's Orthodox Church in Istanbul, on the occasion of its 120th anniversary. In addition to the St. Stephen Church, there is another Bulgarian Orthodox church in Istanbul, St. Demetrius Church, in Feriköy.