Christianity in Europe Christians were part of the Protestant tradition. Russia is the largest Christian country in Europe by population, followed by Germany and Italy. Since at least the legalization of Christianity by the Roman Emperor Constantine in the 4th century, Europe has been an important centre of Christian culture, even though the religion was inherited from Africa and the Middle East and important Christian communities have thrived outside Europe such as Oriental Orthodoxy and the Church of the East since the time of Christ. Christian culture has been an important force in Western civilization, influencing the course of philosophy, art, and science.
Christianity in Europe its state religion in AD 301. The oldest state-built church in the world, Etchmiadzin Cathedral, was built between AD 301-303. It is the seat of the Armenian Apostolic Church. The Roman Empire officially adopted Christianity in AD 380. During the Early Middle Ages, most of Europe underwent Christianization, a process essentially complete with the Baltic Christianization in the 15th century. The emergence of the notion of "Europe" or the "Western World" is intimately connected with the idea of "Christendom", especially since Christianity in the Middle East was marginalized by the rise of Islam from the 7th century, a constellation that