Just like Judaism and Islam, Christianity is an Abrahamic religion. Christianity started out as a Jewish sect in the eastern Mediterranean. It quickly grew in number of believers and influence over a few decades, and by the 4th Century it had become the dominant religion in the Roman Empire. Armenia was the First Nation in the world to adopt Christianity as its official religion, under the rule of King Tiridates III of the Arsacid dynasty in the early 4th century. The Kingdom of Aksum became the first empire to adopt Christianity. During the Middle Ages, the rest of Europe mostly was Christianized. At that time, Christians were mostly a religious minority in the Middle East, North Africa, and parts of India. Following the Age of Discovery, through missionary work and colonization, Christianity spread to Africa, the Americas, and the rest of the world.