Christianity is the largest religion in Germany. It was introduced to the area of modern Germany by 300 AD, while parts of that area belonged to the Roman Empire, and later, when Franks and other Germanic tribes converted to Christianity from the fifth century onwards. The area became fully Christianized by the time of Charlemagne in the eighth and ninth century. After the Reformation started by Martin Luther in the early 16th century, many people left the Catholic Church and became Protestant, mainly Lutheran and Calvinist. In the 17th and 18th centuries, German cities also became hubs of heretical and sometimes anti-religious freethinking, challenging the influence of religion and contributing to the spread of secular thinking about morality across Germany and Europe.
Albania is a secular and religiously diverse country with no official religion and thus, freedom of religion, belief and conscience are guaranteed under the country's constitution. Islam is the most common religion in Albania, followed by Christianity, though religiosity is low and there are many irreligious Albanians. In the 2023 census, Muslims accounted for 51% of the total population, Christians made up 16%, while irreligious were 17%. The other 16% were undeclared.
Orthodox Christianity is the most widely professed faith in Russia, with significant minorities of non-religious people and adherents of other faiths.
Moldova's constitution provides for freedom of religion and complete separation of church and state, though the constitution cites the "exceptional importance" of Eastern Orthodox Christianity. Discrimination on the basis of religious affiliation is illegal, and incitement to religious and ethnic hatred was made illegal in May 2022. Religion in Moldova is dominated by the Eastern Orthodox branch of Christianity. According to the 2014 Moldovan census, 90 per cent of the country reported to be of the Eastern Orthodox Christian faith. Of this number, around eighty to 90 per cent of Orthodox Moldovans belong to the Moldovan Orthodox Church which is subordinate to the Russian Orthodox Church, and has played a powerful role in deepening Russia's influence in Moldova. The remaining 10–20 per cent of Orthodox Moldovans belong to the Metropolis of Bessarabia, which is subordinate to the Romanian Orthodox Church.
Religion has been a major influence on the societies, cultures, traditions, philosophies, artistic expressions and laws within present-day Europe. The largest religion in Europe is Christianity. However, irreligion and practical secularisation are also prominent in some countries. In Southeastern Europe, three countries have Muslim majorities, with Christianity being the second-largest religion in those countries. Ancient European religions included veneration for deities such as Zeus. Modern revival movements of these religions include Heathenism, Rodnovery, Romuva, Druidry, Wicca, and others. Smaller religions include Indian religions, Judaism, and some East Asian religions, which are found in their largest groups in Britain, France, and Kalmykia.
Evangelical Protestantism is one of five officially recognized faiths in Albania. It is a Christian faith that views Jesus Christ as its founder and head, and the Bible as its written authority.
Serbia has been traditionally a Christian country since the Christianization of Serbs by Clement of Ohrid and Saint Naum in the 9th century. The dominant confession is Eastern Orthodoxy in the fold of Serbian Orthodox Church.
Eastern Orthodox Christianity is largest religion in Montenegro, but there are also sizeable numbers of adherents of both Catholic Christianity and Islam.
Religion in Ethiopia consists of a number of faiths. Among these mainly Abrahamic religions, the most numerous is Christianity totaling at 67.3%, followed by Islam at 31.3%. There is also a longstanding but small Ethiopian Jewish community. Some adherents of the Baháʼí Faith likewise exist in a number of urban and rural areas. Additionally, there is also a substantial population of the adherents of traditional faiths.
Christianity is the predominant religion in Ukraine, with 85% of the population identifying as Christian according to a 2022 survey conducted by the Kyiv International Institute of Sociology (KIIS). Seventy-two percent of the population avowed fidelity to an Eastern Orthodox Church: 54% of Ukrainians proclaimed adherence to the autocephalous Orthodox Church of Ukraine; 14% identified as Orthodox Christian without specifying a church affiliation; 4% associated with the Moscow Patriarchate. Another 9% of Ukrainians professed devotion to the Catholic Church in Ukraine: 8% Ukrainian Greek Catholics and 1% Latin Catholics. Two percent of the population declared affiliation to a mainstream Protestant Church, and a further 2% identified with some alternative sect of Christianity.
After the October Revolution, there was a movement within the Soviet Union to unite all of the people of the world under communist rule known as world communism. Communism as interpreted by Vladimir Lenin and his successors in the Soviet government included the abolition of religion and to this effect the Soviet government launched a long-running unofficial campaign to eliminate religion from society. Since some of these Slavic states tied their ethnic heritage to their ethnic churches, both the peoples and their churches were targeted by the Soviets.
The dominant religion in Slovenia is Christianity, primarily the Catholic Church, which is the largest Christian denomination in the country. Other Christian groups having significant followings in the country include Eastern Orthodoxy and Protestantism (Lutheranism). Islam, Judaism and Hinduism are small minorities in Slovenia. About 18% of the population are either agnostic or atheist.
Christianity is the main religion in Belarus, with Eastern Orthodoxy being the largest denomination. The legacy of the state atheism of the Soviet era is apparent in the fact that a proportion of Belarusians are not religious. Moreover, other non-traditional and new religions have sprung up in the country after the end of the Soviet Union.
Christianity in Uzbekistan is a minority religion.
Christianity is the predominant religion in Georgia. The wide variety of peoples inhabiting Georgia has meant a correspondingly rich array of active religions in the country.
Religion in Kosovo is separated from the state. The constitution of Kosovo establishes it as a secular state that is neutral in matters of religious beliefs and where everyone is equal before the law and freedom of religion or belief is guaranteed.
In North Macedonia, the most common religion is Eastern Orthodox Christianity, practiced mainly by ethnic Macedonians, Serbians, Vlachs, and Romanis. The vast majority of the Eastern Orthodox in the country belong to the Macedonian Orthodox Church, which declared autocephaly from the Serbian Orthodox Church in 1967.
Estonia, historically a Lutheran Christian nation, is today one of the least religious countries in the world in terms of declared attitudes, with only 14 percent of the population declaring religion to be an important part of their daily life. This is thought to largely be a result of the Soviet occupation of Estonia in 1940, prior to which Estonia had a large Christian majority.
Eastern Orthodoxy arrived in the areas of Illyrii proprie dicti or Principality of Arbanon during the period of Byzantine Empire. Those areas fell under the Ottoman Empire during the late medieval times and Eastern Orthodoxy underwent deep sociopolitical difficulties that lasted until the fall of the Ottoman Empire. Between 1913 and until the start of WWII under the newly recognized state of Albania, Eastern Orthodoxy saw a revival and in the 1937 the Autocephaly after a short Eastern Orthodoxy schism and contestation was recognized. Decades of persecution under the Communist state atheism, which started in 1967 and officially ended in December 1990, greatly weakened all religions and their practices especially Christians of Albania. The post-communist period and the lifting of legal and other government restrictions on religion allowed Orthodoxy to revive through institutions and enabled the development of new infrastructure, literature, educational facilities, international transnational links and other social activities.
The main religion traditionally practiced in Latvia is Christianity. As of 2019, it is the largest religion (68.84%), though only about 7% of the population attends religious services regularly.
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