Istanbul is famous for its mosques, its bazaars and the Bosphorus, but for more than eleven centuries this city was Constantinople, the capital of the Christian Roman world. The top Christian sites in Istanbul are Hagia Sophia, Hagia Irene, the Hippodrome, Little Hagia Sophia, the Archaeological Museums, the Church of the Pantokrator, the Ecumenical Patriarchate in Fener, the Chora Church, the Theodosian Walls, the Balıklı Monastery, St. Anthony of Padua and the Monastery of St. George on Büyükada.
I grouped them below by neighborhood, so you can see them without crossing the city back and forth.
Why Istanbul Matters So Much for Christian History
There is probably no city in the Christian world that carries more historical weight than Istanbul. I say this knowing very well what Rome and Jerusalem mean for people, and I still stand by it.
Emperor Constantine the Great chose this peninsula between Europe and Asia for his New Rome and dedicated the city in 330 AD. From then until the Ottoman conquest in 1453, Constantinople was the capital of the Byzantine Empire, and for most of those centuries it was the biggest Christian city on earth.
The list of Christian names connected to the city is long. Gregory of Nazianzus preached his famous Five Theological Orations here in 380, and he led the council of 381 for a short time before he resigned. John Chrysostom, the “golden-mouthed” preacher, was Archbishop of Constantinople and he was sent into exile from this city for two times.
Emperor Justinian, who gave the world Hagia Sophia as we know it, was buried here in the Church of the Holy Apostles. That church does not stand anymore, the Fatih Mosque was built on its place.
Church councils met in Constantinople in 381, 553 and 680–681, and all three are counted as ecumenical councils. Another council met here in 869–870, which the Catholic Church counts as the eighth ecumenical council but the Orthodox Church does not. In addition, the Ecumenical Patriarchate, the first see of the Orthodox Church, still works in the Fener district on the Golden Horn.
By the way, there is a strong Ephesus connection too. Nestorius, an Archbishop of Constantinople, was condemned at the Council of Ephesus in 431, and Justinian, who built Hagia Sophia, also built the great Basilica of Saint John nearby Ephesus. As an Ephesian guide I always say that Istanbul and Ephesus are two chapters of same story.
Christian Sites Around Sultanahmet
Let’s have a look at the sites around Sultanahmet first. The first five places are all close to each other and you can walk between them in few minutes.
1. Hagia Sophia (Ayasofya)
The great church of Justinian was consecrated in 537 AD after only five years of construction, and for nearly a thousand years it was the largest church in the world. Standing inside the huge dome for the first time is one of those experiences that simply does not fit in a photograph.
Hagia Sophia was converted into a mosque in 1453, became a museum in 1934 and was converted into a mosque again in 2020. Whatever one thinks about its status today, the building itself, with its pendentives, half-domes and colored marble, is one of the greatest achievements of human architecture.
A visiting note, checked in October 2026: since January 2024 foreign visitors enter Hagia Sophia from a separate door and see it from the upper gallery, while the ground floor is kept for worship. The ticket is 25 euros and museum passes are not valid. The good news is that the upper gallery is where the famous Deesis mosaic of Christ, the Virgin Mary and John the Baptist is. You can read more about its history in my Hagia Sophia article.
2. Hagia Irene (Aya İrini)
Just behind Hagia Sophia, inside the first courtyard of Topkapı Palace, stands Hagia Irene, the church of the Holy Peace. Its foundation goes back to the 4th century, so it is often called the first church of the city, and the Second Ecumenical Council traditionally met here in 381. This is the council that completed the Nicene Creed, which most churches still recite today.
Justinian rebuilt the church after the fire of 532. Hagia Irene was never turned into a mosque. The Ottomans used it as an arsenal for a long time. Look up to the apse when you go inside: the simple black cross there dates back to the Iconoclast period, when images of saints were not allowed in the churches. Hagia Irene is a museum today with its own ticket, and the Müzekart museum pass is not valid here, so plan to buy the ticket on the door.
3. The Hippodrome (Sultanahmet Square)
The Hippodrome of Constantinople, Sultanahmet Square today, was the civic heart of the Byzantine city. It saw chariot races, imperial ceremonies, public executions and the Nika Riots of 532, when Justinian nearly lost his throne and the old Hagia Sophia was burned down.
Three monuments still stand on the line of the old race track: the Egyptian Obelisk of Theodosius, the bronze Serpent Column brought from Delphi, and the Walled Obelisk. I wrote about them in detail in Mysterious Monoliths of Istanbul. Walking around the square is the easiest way to feel the Byzantine city sleeping under modern one.
4. Little Hagia Sophia (Church of Saints Sergius and Bacchus)
Justinian built this church between 527 and 536 AD, so it was started before the great Hagia Sophia. In some ways it feels more personal than its big sister. It was converted into a mosque in the early 1500s and it still works as a mosque today.
Inside, a long Greek inscription runs around the entablature, honoring Justinian, his empress Theodora and Saint Sergius. The octagonal plan and the quality of the column capitals make it an important building in Byzantine architecture. The quiet streets around it, going down toward the sea walls, are among the most charming corners of old Istanbul.
5. Istanbul Archaeological Museums
The museum complex nearby Topkapı Palace keeps a lot of early Christian and Byzantine material: sarcophagi, architectural pieces, inscriptions and objects from all over Anatolia and the Near East. Look for the early Christian sarcophagi carved with crosses and Christ monograms. The complex also keeps the Temple Warning inscription from the Second Temple of Jerusalem, which I wrote about in my Soreg Inscription article.
The collection goes from Neolithic times to the end of Byzantium, and this helps to see Christian history in its real, enormous context. The same museum also keeps the famous Alexander Sarcophagus, so you should plan at least two hours for here.
Christian Sites Along the Golden Horn and the Land Walls
The second group is spread along the Golden Horn and the old land walls. You need a taxi, a car or good walking shoes for this part of the city.
6. Zeyrek Mosque (Church of Christ Pantokrator)
Fewer people visit this building than it deserves. The Monastery of Christ Pantokrator was one of the most important monasteries of Byzantine Constantinople. It was built in the 12th century by Emperor John II Komnenos and his wife Empress Eirene, and it served as the burial place of the Komnenos family. It also had a well-known hospital too.
The complex, a mosque today, stands on a hill in the Fatih district with a beautiful view over the Golden Horn.
Here is a detail I love as a guide from Ephesus. Around 1169 Emperor Manuel I Komnenos brought a slab of red porphyry from Ephesus to Constantinople. People believed it was the stone on which the body of Christ was laid after the Crucifixion, and Byzantine writers tell that the emperor carried it himself.
The stone was kept here at the Pantokrator, where Manuel himself was later buried. Nobody knows where it is today, but the story shows how holy Ephesus still was for Byzantines, more than a thousand years after Saint Paul.
7. The Ecumenical Patriarchate and the Church of St. George (Fener)
The spiritual center of Orthodox Christianity sits quietly in Fener district on the Golden Horn, in a small and modest compound for an institution of such importance. The Ecumenical Patriarch, Bartholomew I since 1991, is the first among equals of the Orthodox bishops and the spiritual leader of some 300 million Orthodox Christians around the world.
The Patriarchate has been in this city since the 4th century and in Fener since about 1600, even though the city around it changed completely. The Church of St. George inside the compound is open to visitors. Its outside looks simple, because the Ottomans limited the height and grandeur of Christian buildings for most of their rule.
Inside, however, it keeps some of the most important objects of the Orthodox world: the patriarchal throne traditionally connected with Saint John Chrysostom, a piece of the column on which Christ is believed to have been flogged, and the relics of Saint Euphemia. In 2004 Pope John Paul II returned the relics of Saint Gregory the Theologian and Saint John Chrysostom to this church, so the two great archbishops of Constantinople are back in their city.
Attending a liturgy here, if you have the chance, is an experience of the living Byzantine tradition that no museum can give. The colorful houses of Balat are a short walk away, so you can combine the two easily.
8. Chora Church (Kariye Mosque)
If Hagia Sophia impresses with its size, the Chora Church amazes with its details. The building we see today mostly dates from the late 11th century, and in the early 14th century the statesman Theodore Metochites decorated it with mosaics and frescoes. They are among the finest examples of late Byzantine art anywhere in the world.
The mosaic cycle of the life of the Virgin Mary is extremely detailed, and the fresco of the Anastasis in the side chapel, Christ pulling Adam and Eve out of their tombs, is simply glowing.
The Chora became a mosque again in May 2024. As of October 2026 foreign visitors pay a 20 euro ticket and the building is open for worship only on Fridays. The mosaics in the outer halls can be seen freely, while some of the images in the prayer hall are covered with curtains. Go in the morning when the light is the best.
9. The Theodosian Walls
The great land walls of Constantinople were built under Emperor Theodosius II in the early 5th century and rebuilt after the earthquake of 447. They are one of the most remarkable pieces of military architecture in history. They protected the city for more than a thousand years, until 1453, when the Ottoman cannons battered them for weeks and the city finally fell.
You can walk along some parts of the walls today and this is one of the best ways to feel how big was the Byzantine city. Some parts are restored, some are crumbling, and all of them are full of atmosphere. The Chora Church is a short walk from the Edirnekapı gate, so these two go well together.
10. Balıklı Monastery of the Life-Giving Spring (Zeytinburnu)
The Balıklı complex in the Zeytinburnu district, just outside the land walls, is one of the oldest living Greek Orthodox places in Istanbul. Its holy spring has been connected with healing miracles since Byzantine times, and people still come here for its holy water. Graves of several Ecumenical Patriarchs are laying in the cemetery next to it.
The fish in the spring give the place its Turkish name, balıklı means “with fish”. There is a lovely legend about them: on the day Constantinople fell in 1453, a monk was frying fish when he heard the news. He said he would believe it only if the fish jumped out of the pan, and the fish jumped back into the spring. We still call the place Balıklı because of that story.
Beyoğlu and the Princes’ Islands
11. Church of St. Anthony of Padua (İstiklal Avenue)
The largest active Roman Catholic church in Istanbul stands on the most famous pedestrian street of the city. It was built between 1906 and 1912 by the Italian community in a red brick neo-Gothic style, and it looks a bit surprising among the shops and the noise of İstiklal. When you step inside from the crowd, the calm is incredible.
Mass is celebrated regularly in several languages. Angelo Roncalli, who later became Pope John XXIII, preached here during his years in Istanbul as the Pope’s representative between 1935 and 1944. It is not an ancient site, it is a living community, and living communities are part of Christian history too.
12. Monastery of St. George on Büyükada (Princes’ Islands)
The Princes’ Islands were a place of exile for unwanted members of the Byzantine royal family, and sometimes for unwanted bishops too. On Büyükada, the largest island, the Monastery of St. George stands on top of the highest hill, and you reach it with a steep walk. The views back toward Istanbul are magnificent. The monastery is still a living Greek Orthodox community.
The city ferries take about 35 minutes from Bostancı on the Asian side and about an hour and 45 minutes from Kabataş on the European side, and the timetables change by season. Going on St. George’s day, April 23, when thousands of people climb the hill to make a wish, is an experience unlike anything else in Turkey. By the way, many of these pilgrims are Muslim Turks and this tells a lot about how faiths still share holy places in this country.
How I Would Plan the Christian Sites of Istanbul
I recommend my guests to give at least two full days to these twelve places. On the first day, Sultanahmet: Hagia Sophia, Hagia Irene, the Hippodrome, Little Hagia Sophia and the Archaeological Museums. On the second day, the Golden Horn: Zeyrek, the Patriarchate, Balat, the Chora Church and the walls, and Balıklı if you have time, then an evening walk on İstiklal Avenue to St. Anthony of Padua. Büyükada needs half a day by itself.
Please keep it in mind that four of these buildings are working mosques today: Hagia Sophia, Little Hagia Sophia, Zeyrek and the Chora. Shoulders and knees should be covered, women should cover their hair, and shoes come off in the prayer halls. At the big mosques they give free of charge scarves and covers at the entrance.
Tourist visits pause during the prayers, and the Chora is open for worship only on Fridays, so plan the Mosques for the other days if you can. Churches like St. George in Fener and St. Anthony are working churches as well, so modest clothes and a quiet voice are always welcome.
If your trip continues to the Aegean coast, my list of Christian sites in Izmir and the Smyrna region is the next chapter, and my guide to Christian Turkey for first-time visitors will help you plan the whole journey.
Frequently Asked Questions
Are there active churches in Istanbul today?
Yes. Istanbul still has many working churches: Greek Orthodox, Armenian, Catholic, Syriac and Protestant. The Ecumenical Patriarchate and its Church of St. George in Fener, the Balıklı Monastery and the Catholic Church of St. Anthony of Padua on İstiklal Avenue all hold regular services, and visitors are welcome when they dress modestly.
Which churches in Istanbul were converted into mosques?
The best-known examples are Hagia Sophia, the Chora Church (Kariye Mosque), Little Hagia Sophia (the Church of Saints Sergius and Bacchus) and the Pantokrator Monastery (Zeyrek Mosque). All four can be visited outside prayer times. Hagia Irene was never converted and is a museum today, and the small Church of St. Mary of the Mongols in Fener has always remained a Greek Orthodox church.
What is the oldest church in Istanbul?
The oldest church building still standing in Istanbul is the basilica of the Stoudios Monastery, built in the 450s and known later as the İmrahor İlyas Bey Mosque. It has been under restoration since 2023 and cannot be visited inside yet. Hagia Irene is often called the first church of the city, because its foundation goes back to the 4th century, although the building we see today is from the 6th century.
Is there a Catholic church in Istanbul?
Yes. The Church of St. Anthony of Padua on İstiklal Avenue is the largest Catholic church in Istanbul, and Mass is celebrated there regularly in several languages. The Catholic cathedral of the city is the Cathedral of the Holy Spirit in Harbiye.
Hire Tour Guide for Christian Sites in Istanbul
If you would like to explore the Christian heritage of Istanbul and the rest of early Christian Turkey with a licensed guide, you can write to me. You can see my guiding rates and guiding areas, or reach me through my contact page. Every one of these places has layers, and layers are always better with someone who knows where to look. I hope we will see each other in Istanbul. See you soon, Hasan Gülday.
