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 Christianization of Scandinavia in the High Middle Ages. The notion of "Europe" and the "Western World" has been intimately connected with the concept of "Christendom", and many even consider Christianity as the unifying belief that created a European identity, especially since Christianity in the Middle East was marginalized by the rise of Islam from the 8th century. This confrontation led to the Crusades, which ultimately failed militarily, but were an important step in the emergence of a European identity based on religion. Despite this, traditions of folk religion continued at all times, largely independent from institutional religion or dogmatic theology.