<P> Since the High Middle Ages, most of Europe used to be dominated by Christianity . There are three major denominations, Roman Catholic, Protestant and Eastern Orthodox, with Protestantism restricted mostly to Northern Europe, and Orthodoxy to Slavic regions, Romania, Greece and Georgia . Also The Armenian Apostolic Church, part of the Oriental Church, is in Europe - another branch of Christianity (world's oldest National Church). Catholicism, while typically centered in Western Europe, also has a very significant following in Central Europe (especially among the Germanic, Western Slavic and Hungarian peoples / regions) as well as in Ireland (with some in Great Britain). </P> <P> Christianity has been the dominant religion shaping European culture for at least the last 1700 years . Modern philosophical thought has very much been influenced by Christian philosophers such as St Thomas Aquinas and Erasmus . And throughout most of its history, Europe has been nearly equivalent to Christian culture, The Christian culture was the predominant force in western civilization, guiding the course of philosophy, art, and science . The notion of "Europe" and the "Western World" has been intimately connected with the concept of "Christianity and Christendom" many even attribute Christianity for being the link that created a unified European identity . </P> <P> Christianity is still the largest religion in Europe; according to a 2011 survey, 76.2% of Europeans considered themselves Christians . Also according to a study on Religiosity in the European Union in 2012, by Eurobarometer, Christianity is the largest religion in the European Union, accounting for 72% of the EU's population . </P> <P> Islam has some tradition in the Balkans and the Caucasus due to conquest and colonization from the Ottoman Empire in the 16th to 19th centuries . Muslims account for the majority of the populations in Albania, Azerbaijan, Kosovo, Northern Cyprus (controlled by Turks), and Bosnia and Herzegovina . Significant minorities are present in the rest of Europe . Russia also has one of the largest Muslim communities in Europe, including the Tatars of the Middle Volga and multiple groups in the Caucasus, including Chechens, Avars, Ingush and others . With 20th - century migrations, Muslims in Western Europe have become a noticeable minority . According to the Pew Forum, the total number of Muslims in Europe in 2010 was about 44 million (6%), while the total number of Muslims in the European Union in 2007 was about 16 million (3.2%). </P>

Who comprises the largest ethnic group in eastern europe