Note: The Kingdom of Georgia, the first state associated with Georgians, appeared in the 11th century. Georgians have nothing to do with the Iberians by themselves. Therefore, anything about Georgian identity before that period probably should not be trusted entirely.
Initially, the Georgian Church recognized the supremacy of the Armenian Church partly for political reasons and partly because Christianity came to Georgia from Armenia.
According to the Greek version of the “Life of St. Gregory”, Grigor Lusavorich sent three apostles, Irenokras, Sofrinos, and Tovma, together with Saint Nino to Iberia, Lazika, and Albania (E. Taikanshvili’s 1910 “Sources of Georgian Chronicles, Conversion of Georgia to Christianity” tells about the latter). Greek historians also reported about that.
Solomen, a church historian of the 5th century, said, “I learned that Armenians adopted Christianity before Georgians and other nations” (Solomen, “History”).
According to some sources, in the 4-6th centuries, the Georgian Catholicos was appointed by the Armenian Church’s officials (G. Akinyan, “Kirion – Catholicos of Georgia”, Vienna, 1910).
Armenians and Georgians have had common ways of confession of Christianity. For example, every year, a large caravan of Armenian pilgrims traveled to Mtskheta to worship the holy shrine of the Holy Cross, while a similar Georgian caravan went to Vagharshapat to worship St. Etchmiadzin (“Book of Records” Tbilisi, 1901).
Church rites have had mutual features also. At that time, the Georgian church recognized “matagh” (a sacrifice symbolizing Jesus’ blood shed for humanity), and also “fasting of St. Sarkis”, which still exist in the Armenian Church.
In the case of the split, the main role was played by the Georgian Catholicos Kirion as well as the unshakable position of the Armenian Catholicosate. Here is how it was.
Kirion was born in Javakhk, but he was a Georgian. Becoming an adult, he moved to Cappadocia and converted Orthodoxy. But after returning to his homeland in 594, he had to hide his real doctrines. Moreover, he was employed by the Armenian Catholicos Movses Ehvardetsi (575-604) and was appointed the Chancellor of the Catholic Service.
In 598, the Catholicos of Georgia died, after which a large delegation of Georgian princes and nobles arrived at Etchmiadzin to ask for the appointment of a new Catholicos. After some consultations, the most suitable candidate for the Catholicos of Georgia became Kirion, who was appointed a Catholicos under the name of Samuel II (598-612).
After that, Kirion started stormy campaigns to promote Orthodoxy in Georgia. His efforts were resonating in the whole country, especially after the fall of the Georgian kingdom and the rise of the risk of assimilation of Georgians into another Christian cultures, namely, the Armenian Church.
But for the time being, Kirion did not act openly – the Catholicos of Armenia and his mentor Movses Ehvardetsi was still alive. At the end of 604, Movses Ehvardetzi died, allowing Kirion to operate freely.
The situation developed in his favor as the election of the next Armenian Catholicos was delayed due to the war between Persia and Byzantium. Vrtanes Bagratuni, the brother of the notorious Smbat Bagratuni, was appointed the interim Armenian Catholicos,
During 605, large-scale preparation for the election of a new Catholicos of Armenians was carried out. In 606, a church council was convened to discuss that issue, but a Catholicos was not elected nonetheless. Instead, the council adopted a set of rules, which, in the light of the recent persecution policy of Emperor Mauritius, toughened sanctions against the Byzantine clergy.
In particular, their decree contained a clause restricting any Orthodox clergyman from holding high positions in the Armenian religious system even after repentance.
This decision put Kirion at a disadvantageous position. He decided to separate the church of his country, which has been a trend in Georgia for a long time.
Only a little push was necessary. It was done in the border town of Gadzhenk (Tsurtav) located in the extreme north-east of Gugark province.
The Armenian historian Ukhtanes wrote about the course of those events (“History”, Vagharshapat, 1871):
“The Armenian bishop of this city Movses had a longstanding unfriendly relationship with Kirion. After the adoption of the rules against the Byzantine Orthodox Church, he somehow found out about the “Orthodox past” of Kirion and immediately informed Etchmiadzin about it.
And while they were thinking about what to do, Kirion took a reciprocal step. In the town church of Gadzhenk, local Georgians did not understand a word from the service as it was carried out in Armenian.
Kirion commanded the service in the church to be only in Georgian. At the same time, Etchmiadzin’s officials ordered Movses to immediately make peace with Kirion. Kirion refused to meet Movses halfway and even forced him to flee.
Then, Etchmiadzin sent Kirion a letter, to which he answered evasively. Correspondence continued for a while as no one wanted to give in. In 607, the new Armenian Catholicos was finally elected under the name of Abraham Altabanezi (607-615). He continued to correspond, but to no avail.
The Georgian Church finally broke off the connections with the Armenian Church at the beginning of 609 during the celebration of the Nativity of Christ.
After this, some attempts were undertaken to reunify the two churches, but all of them failed. And after the Georgian Church fell under the full influence of the Greek Church, it took an especially irreconcilable position towards the Armenian Church. To make that more clear and secure, they destroyed all evidence about the once unified church and altered their traditions.
In 1103 at the cathedral in Rab Urbanis, the Georgian Church recognized the Armenian Church heretical.” L. Melikset-Beck, «Грузинский извод сказании о посте Араджавор», Petrograd, 1917.