The Church was founded by Jesus Christ (cf. Matthew 16:18; 28:19-20). According to tradition, two of His Apostles --St. Thaddeus and St. Bartholomew-- preached His Gospel in Armenia as early as the second half of the first century. Then in 314 , St. Gregory the Illuminator formally established the Church in Armenia, when King Tiridates III was baptized and declared Christianity as the state religion. St. Gregory (c. 240-325 AD) was a descendant of a noble house in Parthia, who was brought up as a Christian in Cappadocia. He was consecrated a bishop by Leontius, the metropolitan of Caesarea, as the first Bishop of Armenia. The origin of the Armenian liturgical and sacramental tradition is ascribed to him. He began his missionary work in Armenia during the first decade of the 4th century, while a layman, and upon is consecration as Bishop he established the Armenian nation's Holy See in Vagharshapat (Etchmiadzin). He is called Illuminator because he "enlightened the nation with the light of the gospel" through baptism.
The Christianization of Armenia "determined the entire future course of Armenian history". The Armenian nation embraced Christ in its own land where God himself "descended". <Etchmiadzin>, literally, means "the only begotten descended. "According to tradition, St. Gregory saw Christ in a vision who indicated to him where to build His Church, the first Armenian Church. As the new Faith took roots in the life of the nation, the invention of an Armenian alphabet was necessitated. Realizing the needs of the Armenian faithful, in 406, St. Mesrob Mashdotz created the Armenian alphabet, under the auspices of Catholicos Sahag, in order to make the Christian faith accessible to the people in a written form. Greek and Syriac were the languages used in the church services. Soon after the invention of the alphabet, St. Mesrob together with St. Sahag and a group of associates --known as Holy Translators-- translated the Holy Scriptures into Armenian, followed by the biblical, theological and liturgical writings of eminent church fathers. This most important era is known as the Golden Age of Armenian history. "The missionary and literary labours [of this period] shaped the destiny of the Armenian people and Church for succeeding generations. [St. Mesrob and St. Sahag, their disciples and co-workers] spearheaded the creation of the Armenian Christian culture under the patronage of the King Vramshapuh. This period was one of intense activity and rapid development for the Church and was decisive in its consolidation and nationalization".
One of the most significant events in Armenian Christianity is the battle of Avarair. Toward the middle of the fifth century, Armenia faced growing pressures from the Persian King Yazdegert II, who had issued an edict bidding the Armenians to renounce Christ and embrace Zoroastrianism. The Armenians remained loyal to their faith, repeatedly refused to disavow Christ. In 451, headed by the commander-in-chief Vartan Mamikonian, Armenians fought against the Persians to preserve their faith. Yeghishe, the historian who wrote <The History of Vartan and the Armenian War>, in a dialogue between the Persian Tenshabuh (ambassador) and the Priest Ghevont, expresses the profundity of this faith, "Christ, the living and life-giving true God, by His beneficent will became the healer of souls and bodies and Himself first suffered tortures and pains to cure the entire human race. He granted us second birth in health without pains and afflications". St. Vartan fell in the battle field of Avarair and Armenians were physically defeated. For the next thirty years oppression and resistance followed, until 484 A.D., when under the leadership of Vahan Mamikonian, Vartan's nephew, the Persian King Peroz reversed course and declared full toleration of Christian faith and the formal recognition and establishment of the Church, in the treaty of Nuarsak.
The following centuries were difficult periods for the Armenian nation --Persian rule (430-634) and later Arab domination (c.654-851). In the 9th century (c. 885) there was an independent kingdom of the Bagratids in Armenia, however it ended in 1079. In the medieval Kingdom of Cilicia or Lesser Armenia, there was an independent entity from the end of the 12th century to 1375. Persecution and martyrdom had become common occurrences in the life of the Armenian nation. A larger proportion of Armenians were massacred by the Turks in the Ottoman Empire starting in the late 19th century to early 20th century. Armenians also suffered under the Russians starting in 1893 until the early 1980s.
In assessing history and the role of the Armenian Church in the life of the Armenian nation, Abp. Aram Keshishian writes: "Confessing Christ has become the quintessence of our history. The history of the Armenian Church in all its manifestations and achievements, conflicts and struggles, is in the fullest sense of the term the history of confessing Christ in action. All the spheres of our life were touched by the transforming power of Christ. The Armenian culture in particular with its spiritual depth and transcendent dynamism has provided the Church with creative insights and new perspectives and horizons in terms of integrating Christ into the ethos of the Nation".