The man who initiated the conversion of Armenia was St. Gregory, called the "Enlightener" or "Illuminator" of Armenia. 
Gregory was the scion of a noble family and was educated in Caesarea, then a Christian center.
He entered the service of King Tiridates of Armenia and after much persecution succeeded in converting the King in ad 301.

Tiridates in turn helped Gregory to convert the whole country to Christianity.  In some regions this took place with relative ease;
in others evangeli­zation met great resistance.  With the help of the King, Gregory destroyed the pagan sanctuaries
and crushed the armed opposition of the pagan priests.  Paganism lingered, however, in the remote parts of the country.

Gregory was formally designated as the supreme head of the Church, and was sent to Caesarea to be ordained a bishop. 
He thus became the first in an unbroken line of 131 catholicoi (or "universal bishops") of the Armenian Church.

Gregory was also instrumental in the conversion of the neighboring countries of Georgia and Albania. 
He built the first Christian cathedral in Vagharshapat, near Mount Ararat, then the capital of Armenia.

Having accomplished his mission and advanced in age, Gregory relinquished the care of the Church to his second son,
Aristakes, who already had been serving as his vicar gen­eral, and in that capacity had attended as a delegate of the
Armenian Church the fa­mous Council of Nicea, in ad 325.  Gregory then retired from active life to live as a hermit until his death.

In time, the heathen gods disappeared and the profession of Christianity be­came general.  The fundamentals of the internal
organization of the Church and its disci­pline were established.  Rituals and church services took definite form.  Aside from
its moral and spiritual benefits, the adoption of Christianity helped to unite the various racial elements and divisions in Armenia,
and forged them into a nation with a distinct identity.