History of religion in Yerevan begins in I century AD, when the first Christian preachers came to this region. Traditionally Thaddeus and Bartholomew (Christ's apostles, who went on a mission to this part of the world) are considered to be the founders of the Armenian Apostolic Church. According to legend, the two preachers were painfully murdered by king Sanatruk because they converted into new religion near relatives of the king.
It is only known that Christianity was widely spread in the neighboring countries of the Caucasus, which had close cultural links with Armenia. At the beginning of IV century, in 301 year, Armenia became the first country in the world, which adopted Christianity as state religion. This happened during the reign of King Trdat III due to the efforts of Gregory I the Illuminator. By the way, the Church got name of Armenian Gregorian one in honor of Gregory. Etchmiadzin Cathedral was built in 303 year near Yerevan. It is still the major center of Armenian Christians. Later, in the V century the Bible was translated into Armenian language.
In the middle of V century Armenian Apostolic Church separated from the Eastern (Byzantine) and Western (Roman) churches. The case was in different interpretation of biblical texts.
So the Armenian Church recognizes only the divine principle of Christ and denies the presence of human in him. They also have their own rules for infant baptism, anointing and other practices. Armenians do not believe in purgatory, strictly observe the fasts and have less religious holidays. And the main prayer is Hyre Mer (Our Father), uttered in ancient Armenian language.
All the religious life of the Armenian Apostolic Church holds in the Etchmiadzin Cathedral: the Supreme Council of church representatives from all over the world gathers here. Every Armenian should come here at least once in a lifetime. Close to Etchmiazdin Cathedral there are two churches of the St. Ripsime and St. Gayane, which are traditional architectural monuments of Armenia.
Other religion existing in the territory of Armenia, including Yerevan, is Islam. History of the country has periods when Islam was the dominant religion, but in the course of various historical events has lost its power. Karabakh conflict in 1980 was the last event that caused many Muslims, residing in Armenia, to leave this country. However, today the representatives of Islam, Christianity and other religions have achieved the tolerance.