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 2021, around 52.7% of the population were Christians among them 49.7% members of the two large Christian churches. About half of Christians in Germany are Catholics, mostly Roman Catholics; Catholicism is stronger in the southern and the western part of the country. About half belongs to the Evangelical Church of Germany (EKD) predominant in the northern regions, and the rest to several small Christian denominations such as the Union of Evangelical Free Churches in Germany, the Eastern Orthodox Church or the Jehovah's Witnesses. Estimations for the percentage of Muslims vary between 3.5% and 6.7%, while much smaller religions include Buddhism, Judaism, Hinduism and Yazidism. The rest of the population is not affiliated with any church, and many are atheist, agnostic, or otherwise irreligious. 60% of German residents say that they believe there is a God, 9% say that they believe there is a higher power or spiritual force and 27% say that they do not believe there is a God, higher power or spiritual force. In another survey, 44% said that they believe there is a God, 25% said that they believe there is some sort of spirit or life force and 27% said that they do not believe there is any sort of spirit, God or life force. 35% of residents identify with their religion or belief. Demographics of religion in Germany vary greatly by region and age. Non-religious people represent the majority in some of Germany's major cities, including Berlin, Hamburg and Bremen, and the absolute majority of 70–80% in the eastern states of what between 1949 and 1990 used to be East Germany. By contrast, rural areas of the western states of what in the same period used to be West Germany are more religious, and some rural areas are highly religious. History Paganism and Roman settlement (1000 BC–300 AD) Ancient Germanic paganism was a polytheistic religion practised in prehistoric