It was was cast in Vienna, floated down the Danube on 100 barges, and bolted together here in Istanbul in 1871.
In December 2017, seven years of extensive restorations were completed. Ninety percent of the church was affected. In 2018 the church reopened to the public.
This was the cathderal church of the Bulgarian Exarch, a title and position invented by the Ottoman sultan when, in the later 1800s, the sultan's Bulgarian subjects demanded to be emancipated from the authority of the Greek Orthodox Patriarch.
At this time of ethnic nationalism, the Bulgarians claimed, with justification, that the patriarch favored Greeks over Bulgars even though both were orthodox Christians.
The "palace" of the Bulgarian Exarch was the building right across the street from the church. It's hardly palatial, especially today.
The church is still used for services by Istanbul's small, dwindling community of Bulgarian orthodox residents.
To visit the church interior after restoration is complete, you must find the caretaker, not an easy task as there are no formal visiting hours. Sunday morning, when services are held, may be the best time.
At any time you can admire the exterior of the church from a Golden Horn cruise. More...
Other Cast-Iron Churches
Tradition has it that an identical church was cast and erected in Vienna, but was destroyed by bombs in war.
In the mid- to late-19th century, cast iron was a very popular building material—witness the career and works of Gustave Eiffel. Paris has no complete cast-iron church to match Istanbul's St Stephen, but it has one church with an all cast-iron frame, the Église Saint-Eugène-Sainte Cécile, and another in which cast iron was used extensively, the great Église Saint-Augusin. (For more on Paris architecture, see ParisTravelPlanner.com.)