In a grand ceremony, leaders from Turkey and Bulgaria are expected to inaugurate Sveti Stefan, an iconic Bulgarian church on Istanbul's Golden Horn shore, this Sunday.

The 19th century church built by the Bulgarian community in Istanbul is the latest place of worship restored in Turkey's drive to bring churches back to their former glory. Also known as the "Iron Church", it will open with a ceremony, which President Recep Tayyip Erdoğan and Bulgarian Prime Minister Boyko Borisov are expected to attend.

Sveti Stefan is branded as the only church mainly made of iron in the world, but it fell into a state of disrepair. Restoration started seven years ago in a project co-funded by Turkey and Bulgaria. Restoration of the church in Balat, a historic neighborhood, is overseen by a foundation of the Bulgarian community in Turkey.

An outstanding symbol of Bulgarian Orthodox Christianity, the church was built in 1898 on the site of a wooden church destroyed in a fire. An Austrian contractor was hired for the construction and 500 tons of iron components were brought from Austria for the construction. The components were pieced together before it opened on Sept. 8, 1898. With three domes and rich exterior decoration, the church stands out among many other Orthodox churches in Istanbul. Six bells in the bell tower were brought from Yaroslavl, Russia, but only two have survived to the present day. The cross-shaped basilica has a ground floor, a basement, a gallery and a spire.

Speaking to Daily Sabah, Istanbul Mayor Mevlüt Uysal said the municipality took up the restoration work upon instructions from Erdoğan. "Istanbul is a city with a great historic heritage that needs to be preserved for the future. We aim to show that coexistence is possible with diverse faiths, languages and cultures," Uysal said.

The mayor said that the municipality first worked on repairs in 2005, when it was found that the church's foundation was weak and needed reinforcement. "More comprehensive work started in 2011 because the building was heavily corroded. We could have forever lost this only surviving iron church in the world," he said.

Among the work done on the church is reinforcement of three exterior walls, reinforcement of the basement, repairs to cracks in the basement walls, insulation, replacement of stained iron columns and more importantly, repainting the dilapidated façade and ornaments. The mayor said the marble floors were also replaced and they kept the floors' authenticity intact during the restoration. They also installed cast iron decorations in the interior again after restoring them. The church's courtyard walls were also restored along with iron railings. "In total, more than TL 13 million [$3.5 million] was spent," the mayor said.

In return for the restoration, the Bulgarian government pledged to authorize restoration of the Ottoman-era mosque Dzhumaya Mosque in Plovdiv. This mosque, built in the 14th century, is one of the oldest Ottoman or Islamic landmarks in Europe. "It is an important symbol especially for Muslims and Turks in Bulgaria," Uysal said, adding that the mosque was once about to collapse because of disrepair before the restoration the Istanbul municipality completed in 2008 and it reopened for worship.

Uysal believes the restoration of Sveti Stefan will draw more visitors to Istanbul by creating a drive for faith tourism. "The city is an open-air museum with thousands of artifacts and buildings and is a significant city for faith tourism. For instance, Suriçi [an old, concentrated quarter of Istanbul] has 340 Ottoman-era mosques, 95 Orthodox churches, 35 Armenian churches and 22 synagogues and they are all situated along the same route. We have madrassahs and ancient Muslim tombs, Greek Orthodox monasteries and graves of saints sacred for the Armenian and Greek communities. This is a wealth of beauty rarely seen in the world. I believe this beautiful atmosphere makes the city more popular," he said.

Turkey and Bulgaria maintain close ties as well as problems rooted in their shared history. The Turkish-Bulgarian community often complains of negligence for their rights. Uysal said restoration of the church and the mosque in Plovdiv may contribute to the resolution of problems, although he added that "different efforts are needed too." "In the past 15 years, we improved our relations with Bulgaria and although we weren't able to completely resolve the problems of Turks in Bulgaria, we were able to relieve them of some problems on a certain level. Undoubtedly, there is still much work to do and the president displayed a strong will to make a climate of peace and cooperation permanent," he said.

Speaking to Anadolu Agency (AA), Vasil Liaze, president of the Bulgarian Orthodox Church Foundation, said the opening ceremony will be grand, and thanked all parties that have contributed to the restoration of the church. He said thousands of people from Bulgaria are expected to attend the ceremony.

Liaze said Erdoğan initiated the restoration after a request from the Bulgarian minority in the city when he was prime minister. "[Erdoğan] had already helped us when he was Istanbul mayor. We are also neighbors. He is from Kasımpaşa, we're from Balat. We asked him about eight or nine years ago, and he ordered the restoration of the church," Liaze said. He said each part, to the finest detail, was disassembled, repaired, then placed back in its original place. "All the main columns were changed and the Iron Church was made to last for more than 100 years. We are sure it would be chosen as the most beautiful church in Istanbul," Liaze said.

The Bulgarian community in Istanbul traces its history to the 18th century. Although Bulgarians were always present in the Ottoman Empire's capital, their number and settlement flourished in that century. It was Prince Stefan Bogoridi, a Bulgarian Ottoman statesman, who spearheaded the efforts to build a Bulgarian church on the site of Sveti Stefan on land he owned and donated to the church. Like other minorities, the number of Bulgarians dwindled in time, with many returned to Bulgaria or immigrating to the United States and Europe. In 2016, Bulgarian Metochion, a renovated addition to the church, reopened and hosted an exhibition of the history of the Bulgarian community in Turkey. The Metochion, a three-story stone building, was built as an addition, but in time it turned into a community and culture center for the Bulgarian community in Istanbul. It was abandoned for years after it was converted into a school, printing house and then a nursing home throughout its history.

Since the Justice and Development Party (AK Party) came to power in 2002, Turkey has sought to restore the rights of religious minorities as well as the houses of worship of minorities, including those of Assyrians, Jews and Greeks. Many properties have been returned to these minorities decades after they were forcefully confiscated by the Turkish state , while the government continues to pursue a policy of restoring abandoned historical buildings. In 2013, the Bulgarian Orthodox Church was returned a 59,000 square meter plot land in central Istanbul that once belonged to the foundation that ran the church.