Arsacid dynasty of Armenia
As the Arsacid dynasty of Armenia (an eponymous branch of the Arsacid dynasty of Parthia) was the first nation to adopt Christianity as state religion (in 301 AD), and Caucasian Albania and Georgia had become Christian entities, Christianity began to overtake Zoroastrianism and pagan beliefs. With the Muslim conquest of Persia, large parts of the region came under the rule of the Arabs, and Islam penetrated into the region.