Christianity is the largest religion in Belgium, with the Catholic Church representing the largest community, though it has experienced a significant decline since the 1950s. Belgium's policy separates the state from the churches, and freedom of religion of the citizens is guaranteed by the country's constitution.
A lapsed Catholic is a Catholic who is non-practicing. Such a person may still identify as a Catholic, and remains one according to Catholic canon law.
Religion in the United Kingdom is mainly expressed in Christianity, which dominated the land since the 7th century. Results of the 2021 Census for England and Wales showed that Christianity is the largest religion, followed by the non-religious, Islam, Hinduism, Sikhism, Judaism, Buddhism, and Taoism.
The Catholic Church is "the Catholic Communion of Churches, both Roman and Eastern, or Oriental, that are in full communion with the Bishop of Rome ." The church is also known by members as the People of God, the Body of Christ, the "Temple of the Holy Spirit", among other names. According to Vatican II's Gaudium et spes, the "church has but one sole purpose–that the kingdom of God may come and the salvation of the human race may be accomplished."
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.
There are 0.8–1.05 billion Protestants worldwide, among approximately 2.5 billion Christians. In 2010, a total of more than 800 million included 300 million in Sub-Saharan Africa, 260 million in the Americas, 140 million in Asia-Pacific region, 100 million in Europe and 2 million in Middle East-North Africa. Protestants account for nearly forty percent of Christians worldwide and more than one tenth of the total human population. Various estimates put the percentage of Protestants in relation to the total number of the world's Christians at 33%, 36%, 36.7%, and 40%, while in relation to the world's population at 11.6% and 13%.
As of the year 2023, Christianity had approximately 2.4 billion adherents and is the largest religion by population. According to a PEW estimation in 2020, Christians made up to 2.38 billion of the worldwide population of about 8 billion people. It represents nearly one-third of the world's population and is the largest religion in the world, with the three largest groups of Christians being the Catholic Church, Protestantism, and the Eastern Orthodox Church. The largest Christian denomination is the Catholic Church, with 1.3 billion baptized members. The second largest Christian branch is either Protestantism, or the Eastern 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.
Christianity is the largest religion in Northern Ireland. In the 2021 census, 79.7% of the Northern Irish population identified as Christians: Catholic (42.3%); Presbyterian (16.6%); Church of Ireland (11.5%); Methodist (2.4%); Other Christian (6.9%). Meanwhile, 1.3% of the population belonged to other religions, 17.4% stated they were non-religious and 1.5% did not state a religious or non-religious identity. The Catholic Church has seen a small growth in adherents, while the other recorded Christian groups have seen a decrease.
Christianity is the largest religion in Luxembourg, with significant minorities of non-religious people and adherents of other faiths.
As of the 2022 census, None was the largest category of belief in Scotland, chosen by 51.1% of the Scottish population identifying when asked: "What religion, religious denomination or body do you belong to?" This represented an increase from the 2011 figure of 36.7%. 38.8% identified as Christian with most of them declaring affiliation with the Church of Scotland and the Catholic Church. The only other religious persuasions with more than 1% affiliation were 'Other Christian' and Muslim at 5.1% and 2.2% of the total population, respectively.
Religion in Italy has been historically characterised by the dominance of the Catholic Church, the largest branch of Christianity, since the East–West Schism. This is in part due to the importance of Rome in the history of the Church, including its historical status as a leading patriarchate and the presence of the Vatican, the Catholic Church's headquarters and the residence of the Pope—the Bishop of Rome—within its borders. However, due to immigration, notably the influx of Muslims, Eastern Orthodox Christians, Protestants, Buddhists and Hindus, as well as proselytism and secularization, religious pluralism in Italy has increased in the 21st century. Italy also features a pre-Christian Jewish community, an autochthonous Protestant church–the Waldensian Evangelical Church and one of the largest shares of Jehovah's Witnesses in the world.
Catholic Christianity is the predominant religion in Malta. The Constitution of Malta establishes Catholicism as the state religion, and it is also reflected in various elements of Maltese culture.
Religion in Austria is predominantly Christianity, adhered to by 68.2% of the country's population according to the 2021 national survey conducted by Statistics Austria. Among Christians, 80.9% were Catholics, 7.2% were Orthodox Christians, 5.6% were Protestants, while the remaining 6.2% were other Christians, belonging to other denominations of the religion or not affiliated to any denomination. In the same census, 8.3% of the Austrians declared that their religion was Islam, 1.2% declared to believe in other non-Christian religions, and 22.4% declared they did not belong to any religion, denomination or religious community.
Religion in Sweden has, over the years, become increasingly diverse. Christianity was the religion of virtually all of the Swedish population from the 12th to the early 20th century, but it has rapidly declined throughout the late 20th and early 21st century.
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.
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 - according to the 1922 census, 99.3% of the Estonian population were Christians.
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.
Irreligion in Ireland pertains to the population of Ireland that are atheist, agnostic, or otherwise unaffiliated with any religion. The 2022 census recorded that 14% of the population was irreligious; the second largest category after Roman Catholicism. The population was traditionally devoutly Catholic throughout much of Ireland's modern history, with a peak of 94.9% identifying as Catholic in the 1961 census. This percentage has declined to 69% in the 2022 census, the lowest recorded. Conversely, those with no religion made up less than 0.1% of the population in 1961; the proportion grew slowly until the 1991 census where it began to rapidly increase to its current share of 14% of the population in 2022.
A decline of Christian affiliation in the Western world has been observed in the decades since the end of World War II. While most countries in the Western world were historically almost exclusively Christian, the post-World War II era has seen developed countries with modern, secular educational facilities shifting towards post-Christian, secular, globalized, multicultural and multifaith societies.
