A world religion
Like Judaism and Islam, Christianity is a monotheistic religion which derives from the middle east, and developed out of first century Judaism. It is sometimes referred to as Abrahamic (i.e. tracing its origins back to Abraham, an ancient Mesopotamian tribal leader from about 2000BC).
Today Christianity is the world’s largest religion, with 2.4 billion adherents in all continents of the world; that is, approx. one third of the world’s population. About half of these affiliate to the Roman Catholic church, and the rest are roughly three quarters protestant and one third Coptic, Greek and Russian Orthodox.
Although modern Christianity has typically been considered as Western-European, its decline in Europe, alongside rapid growth in southern countries and Asia, means that by 2050 it will have a very different demographic from that of the nineteenth and twentieth century Church. By then, most Christians will be non-English speaking, and non-European in ethnicity.
 Center for the Study of Global Christianity (2018), ‘Status of Global Christianity, 2018, in the Context of 1900–2050’, Center for the Study of Global Christianity