All Savior's Cathedral is the most outstanding monument in New Julfa. It is located in the center of Big Square Parish. Cathedral is the seat of Ecclesiastical Council of Gregorian Armenian for Isfahan and Southern Iran, with Archbishop as chairman.

Gregorian Church is independent Christian Communion named for St. Gregory, the Illuminator, and is among the most ancient of Orthodox Christian communions. Through centuries, it has maintained its independence in hierarchy and is sacred liturgy, while it has always shown a policy of ecumenical friendship with all Christian communions.

Cathedral was began in 1606, at the time of arrival of Armenian immigrants to Isfahan. Prior to its completion, there was small church, which served as the center of Gregorian Christianity in Persia. Over the foundation of that small church, the magnificent high altar of Cathedral was built in 1655. Cathedral's design and construction were overseen by Archbishop David and it was completed in 1664.

Alter of Cathedral is named for St. Josef of Arimathia. Relics of that great saint are preserved within the altar. The soaring walls and splendid arches and domes of the building are indented to edify the spirit of the viewer.

From the tiled lower portions of the walls to the ceiling are oil paintings and gilded carvings, which represent the story of god's revelation throughout Old and New Testaments and history of the triumph of St. Gregory, the Illuminator, over his persecutors. They illustrate the biblical narrative from the Creation to triumphant Resurrection of Jesus Christ. This work was completed in the years 1660-1670, under the financial sponsorship of Khoja Avetic; his portrait is shown on the pillar in church corridor.

In the cellar, under the main apses, are entombed the remains of two archbishops:
Khachatour Kesaratzi, who founded Armenian Press of New Julfa, and
David, builder of the altar of Cathedral.