What was the primary religion of Armenians?

The primary religion of Armenians is Christianity, specifically Armenian Apostolic Christianity. Armenia was the first nation in the world to formally adopt Christianity as a state religion, doing so in the early 4th century. Armenian Christianity is an Oriental Orthodox denomination that is not in communion with the Eastern Orthodox Church or the Catholic Church. It has its own unique liturgy, theology, and traditions, and is headed by the Catholicos of All Armenians.