The original church was built in the early fourth century[12]—between 301 and 303 according to tradition—by Armenia's patron saint Gregory the Illuminator, following the adoption of Christianity as a state religion by King Tiridates III.

Armenia's patron saint Gregory the Illuminator had a divine vision descending from heaven and striking the earth with a golden hammer to show where the cathedral should be built.

Էջմիածնի) is celebrated by the Armenian Church 64 days after Easter, during which a hymn, written by the 8th century Catholicos Sahak III, retelling St. Gregory's vision, is sung.

[50] Archaeological excavations in 1955–56 and 1959, led by Alexander Sahinian, uncovered the remains of the original fourth-century building, including two levels of pillar bases below the current ones and a narrower altar apse under the present one.

[58] According to Ghazar Parpetsi, it was rebuilt from the foundations by marzban (governor) of Persian Armenia Vahan Mamikonian in 483/4,[59] when the country was relatively stable,[60] following the struggle for religious freedom against Persia.

[66][i] In the poem, which tells about the consequences of the Mongol and Mamluk invasions of Armenia and Cilicia, Orbelian portrays Etchmiadzin Cathedral "as a woman in mourning, contemplating her former splendor and exhorting her children to return to their homeland [...] and restore its glory.

Concurrently with the deportation of up to 350,000 Armenians into Persia by Shah Abbas I as part of the scorched earth policy during the war with the Ottoman Empire,[72][73] Etchmiadzin was plundered in 1604.

[78] In the event, only some important stones—the altar, the stone where Jesus Christ descended according to tradition, and Armenian Church's holiest relic,[79] the Right Arm of Gregory the Illuminator—were moved to New Julfa.

[60] Decades later, in 1682, Catholicos Yeghiazar constructed smaller bell towers with red tuff turrets on the southern, eastern, and northern wings.

[87][86] Tsitsianov's forces entered Etchmiadzin, which, according to Auguste Bontems-Lefort, a contemporary French military envoy to Persia, they looted, seriously damaging the Armenian religious buildings.

[91] In 1868, Catholicos Gevorg (George) IV made the last major alteration to the cathedral by adding a sacristy (museum and room of relics) to its east end.

[96] Prior to the May 1918 Battle of Sardarabad, which took place just miles away from the cathedral, the civilian and military leadership of Armenia suggested Catholicos Gevorg (George) V to leave for Byurakan for security purposes, but he refused.

[100] During the Great Purge and the radical state atheist policies in the late 1930s, the cathedral was a "besieged institution as the campaign was underway to eradicate religion.

[102] In August of that year, the Armenian Communist Party decided to close down the monastery, but the central Soviet government seemingly did not approve of such a measure.

"For them the ecclesiastical Echmiadzin belongs irrevocably to the past, and even if the monastery and the cathedral are occasionally the scene of impressive ceremonies including the election of a new catholicos, this has little importance from the communist point of view," wrote Walter Kolarz in 1961.

[118] The main benefactors, including diaspora billionaires Noubar Afeyan and Samvel Karapetyan, who had funded to the renovation were awarded by Catholicos Karekin II.

[119] The initial goal was to address the external structure, primarily repairing roof tiles, but significant issues with the cathedral's physical condition were subsequently uncovered.

[120][121] Its 17th century cross, made of thin brass sheets and in a severely deteriorated condition, was replaced with a bronze one that closely replicates its style and size.

[l] Ranuccio Bianchi Bandinelli disagreed, asserting that fourth century Armenian churches, including Etchmiadzin,[m] considerably differ from Justinian-era Byzantine architecture of Constantinople.

[139] He argued that they are local creations that borrow technical elements from the East (Hatra, Sarvestan), but are "fundamentally Hellenistic" in their "formal structure and proportional relationships.

[153] Some like Shahkhatunian and Ghevont Alishan suggested that these reliefs were created before the invention of the Armenian alphabet c. 405, while Sirarpie Der Nersessian believed that they are from the fifth or sixth century.

[167] Porter found the interior "dark and gloomy" with the "ill-drawn, and worse-coloured" paintings and "dingy fresco" adding to the "gloom, without increasing the solemnity.

[2] The design of the cathedral—classified as a "four-apsed square with ciborium,"[173] and called "Etchmiadzin-type" in Armenian architectural historiography[60]—was not common in Armenia in the early medieval period.

[34] Sahinian suggested that Armenian church architecture was spread in Western Europe in the 8th–9th centuries by the Paulicians, who migrated from Armenia en mase after being suppressed by the Byzantines during the Iconoclasm period.

Among its notable exhibits are the Holy Lance (Spear), relics belonging to Apostles of Jesus and John the Baptist, and a fragment of Noah's Ark.

[222] Robert W. Thomson argues that although Etchmiadzin was not the original center of the Armenian Church (which was and remained in Ashtishat until after the division of the country in 387), it had "clearly been a holy shrine" from the "earliest Christian time in Armenia.

"[225] Early European visitors to Etchmiadzin who gave descriptions of the cathedral included Jean-Baptiste Tavernier (before 1668),[226] Jean Chardin (1673),[227] Joseph Pitton de Tournefort (c. 1700),[228] James Morier (1810–16),[229] Robert Ker Porter (1817–20),[144] Friedrich Parrot (1829),[230] Eli Smith and H. G. O. Dwight (1829),[21] August von Haxthausen (1843),[231] Moritz Wagner (1843),[232] Douglas Freshfield (1869),[23] John Buchan Telfer (1870s),[233] James Bryce (1876),[234] H. F. B. Lynch (1893).

"[261] Leaders of several countries, such as Russia (Vladimir Putin in 2005),[262] France (Jacques Chirac in 2006[263] and Nicolas Sarkozy in 2011),[264][265] Georgia (Mikheil Saakashvili in 2004,[266] Giorgi Margvelashvili in 2014),[267] Romania (Emil Constantinescu in 1998),[268] Lebanon (Michel Aoun, 2018),[269] Germany (Angela Merkel, 2018),[270][271] and royalty, such as Nicholas I of Russia (1837),[272] King Mahendra of Nepal (1958),[273] Prince Charles (2013)[274] have visited the cathedral as part of their state or private visits to Armenia.

The floor mosaic, created by the 20th-century Israeli artist Hava Yofe, inside the Chapel of Saint Helena at Jerusalem's Church of the Holy Sepulchre depicts the cathedral along with other major Armenian sites.

[281] In the 1991 film Mayrig, directed by French-Armenian director Henri Verneuil, footage of the cathedral is shown when Azad Zakarian, the main character and a son of Armenian genocide survivors, is being questioned about his faith in a Catholic school.