Armenian Catholics occupy a specific theological position: they are Armenian Christians who entered into full communion with Rome while retaining their own liturgical rite, calendar, and clerical traditions distinct from the Latin Catholic Church. This union developed over centuries of contact between Armenian communities and Catholic missionaries. The archeparchy serves Armenian Catholics in Turkey and falls under the authority of the Armenian Catholic Patriarch of Cilicia — a patriarchate whose history of movement mirrors the displacements of the Armenian people themselves. The cathedral, St. Mary of Sakızağaç, stands in Istanbul as the physical anchor of this community: a place where the Armenian language, the traditional chant, and the sacramental life of an ancient Christian church continue to be celebrated in the heart of a predominantly Muslim city.

Pope Pius VIII formally established the eparchy on 6 July 1830, giving institutional recognition to a Catholic Armenian community that had been present in Istanbul for generations without its own organized diocese. For most of the nineteenth century, the archeparchy's fate was intertwined with the larger Armenian Catholic Patriarchate of Cilicia: from 1866 to 1928, the patriarchal see was itself based in Istanbul, making the city the center of the entire Armenian Catholic world. When the patriarchal seat moved to Beirut, Lebanon, after the upheavals of the early twentieth century, the current archeparchy was formally constituted as an independent see on 15 October 1928 — Istanbul remaining the home of a locally-rooted church even as the wider institution reorganized around it.

By 2008, approximately 3,650 Armenian Catholics belonged to the diocese — a figure that reflects both the community's endurance and the diminishment that the Armenian people suffered in Anatolia during the twentieth century. The early 1900s brought catastrophic losses to Armenian communities throughout the Ottoman Empire; what remained in Istanbul was a remnant of a far larger presence. That the archeparchy continues to function, to celebrate liturgy, to educate, and to maintain its cathedral is a testament to the commitment of those who stayed. The community is modest in size by the standards of global Catholicism, but its continuity across two centuries of institutional life — through wars, demographic upheaval, and the transformation of a great empire into a secular republic — carries its own weight.

The recent history of the archeparchy's leadership reflects both the democratic instincts and the ecclesiastical procedures of Eastern Catholic governance. Archbishop Hovhannes Tcholakian stepped down in March 2015. The Synod of Bishops of the Patriarchal Church elected Boghos Lévon Zékiyan as his successor — a scholar and theologian who had spent decades in Istanbul. In October 2024, Zékiyan in turn resigned, and the Synod appointed Vartan Kirakos Kazanjian, who had served as the archeparchy's protosyncellus, as the new eparchial archbishop. These transitions of authority, conducted through synodal process and in dialogue with Rome, keep a living institution adapting to each generation of the small community it serves.

St. Mary of Sakızağaç Cathedral is more than a place of worship; it is the most visible sign that Armenian Catholics have a continuous home in Istanbul. The building's interior — its liturgical furnishings, its chant, its congregation — represents a link to a form of Christian life that predates the Ottoman Empire and survived its end. In a city where many communities came and went, leaving only architectural traces, the Armenian Catholic community gathers here still. The archeparchy's presence is modest, its profile low, its work largely internal to the community. But that continuity, maintained across nearly two centuries of institutional life since Pope Pius VIII signed the founding decree, is itself a kind of answer to the question of whether a small ancient community can persist in a changing world.