<P> Armenians (Armenian: հայեր, hayer (hɑˈjɛɾ)) are an Indo - European ethnic group native to the Armenian Highlands . </P> <P> Armenians constitute the main population of Armenia and the de facto independent Artsakh . There is a wide - ranging diaspora of around 5 million people of full or partial Armenian ancestry living outside modern Armenia . The largest Armenian populations today exist in Russia, the United States, France, Georgia, Iran, Germany, Ukraine, Lebanon, Brazil and Syria . With the exceptions of Iran and the former Soviet states, the present - day Armenian diaspora was formed mainly as a result of the Armenian Genocide . </P> <P> Most Armenians adhere to the Armenian Apostolic Church, a non-Chalcedonian church, which is also the world's oldest national church . Christianity began to spread in Armenia soon after Jesus' death, due to the efforts of two of his apostles, St. Thaddeus and St. Bartholomew . In the early 4th century, the Kingdom of Armenia became the first state to adopt Christianity as a state religion . </P> <P> Armenian is an Indo - European language . It has two mutually intelligible and written forms: Eastern Armenian, today spoken mainly in Armenia, Artsakh, Iran, and the former Soviet republics; and Western Armenian, used in the historical Western Armenia and, after the Armenian Genocide, primarily in the Armenian diasporan communities . The unique Armenian alphabet was invented in 405 AD by Mesrop Mashtots . </P>

Which nation was the first to accept christianity