Europe of population are Saint Petersburg, Madrid, Berlin and Rome, each having over 3 million residents. When considering the commuter belts or metropolitan areas, within the EU (for which comparable data is available) London covers the largest population, followed in order by Paris, Madrid, Barcelona, Berlin, the Ruhr area, Rome, Milan, Athens and Warsaw. "Europe" as a cultural concept is substantially derived from the shared heritage of the Roman Empire and its culture. The boundaries of Europe were historically understood as those of Christendom (or more specifically Latin Christendom), as established or defended throughout the medieval and early modern history of
Christianity in Europe Christianity in Europe Christianity is the largest religion in Europe. Christianity has been practiced in Europe since the first century, and a number of the Pauline Epistles were addressed to Christians living in Greece, as well as other parts of the Roman Empire. According to a 2010 study by the Pew Research Center, 76.2% of the European population identified themselves as Christians. As 2010 Catholics were the largest Christian group in Europe, accounting for more than 48% of European Christians. The second-largest Christian group in Europe were the Orthodox, who made up 32% of European Christians. About 19% of European