Most Armenians are Christian, primarily of Oriental Orthodox rite.
Christianity was first introduced by the apostles Bartholomew and Thaddeus in the 1st century AD. Armenia became the first country to establish Christianity as its state religion when, in an event traditionally dated to 301 AD, St. Gregory the Illuminator convinced Tiridates III, the king of Armenia, to convert to Christianity. Before this, the dominant religion was Zoroastrianism and to a smaller degree Paganism.
Over 90% of Armenians belong to the Armenian Apostolic Church, a form of Oriental (Non-Chalcedonianism) Orthodoxy, which is a very ritualistic, conservative church, roughly comparable to the Coptic and Syrian churches.
Armenia also has a population of Armenian Apostolic 94.7%, other Christian 4% (mostly Armenian Catholic and Russian Orthodox), Yazidi(monotheist with elements of nature worship) 1.3%, and small Muslim and Jewish populations.