Western Christianity is the type of Christianity which developed in the areas of the former Western Roman Empire. Western Christianity consists of the Latin Rite of the Catholic Church (in contrast to the Eastern rites in communion with Rome), Independent Catholicism, and a wide variety of Protestant denominations. The name "Western Christianity" is applied in order to distinguish these from Eastern Christianity. During the Middle Ages adherents of Western Christianity, irrespective of ethnicity, commonly referred to themselves as "Latins" in order to distinguish themselves from others.
With the expansion of European colonialism from the Early Modern era, Western Christianity spread throughout the Americas, much of the Philippines, Southern Africa, pockets of West Africa, and throughout Australia and New Zealand. Thus, when used for historical periods after the 16th century, the term "Western Christianity" does not refer to a particular geographical area, but is rather used as a collective term for the Catholic Church, the Protestant denominations, and the other forms of Christianity that trace their lineage to Western Europe.
Today, the geographical distinction between Western and Eastern Christianity is not nearly as absolute as in Antiquity or the Middle Ages, due to the spread of missionary activities, migrations, and globalisation. The adjectives "Western Christianity" and "Eastern Christianity" are typically used to refer to historical origins and differences in theology and liturgy, rather than present geographical locations.
For most of its history the church in Europe has been culturally divided between the Latin-speaking west, whose centre was Rome, and the Greek-speaking east, whose centre was Constantinople. Cultural differences and political rivalry created tensions between the two churches, leading to disagreement over doctrine and ecclesiology and ultimately to schism.
Like Eastern Christianity, Western Christianity traces its roots directly to the apostles and other early preachers of the religion. In Western Christianity's original area Latin was the principal language. Christian writers in Latin had more influence there than those who wrote in Greek, Syriac, or other Eastern languages. Though the first Christians in the West used Greek (such as Clement of Rome), by the fourth century Latin had superseded it even in the cosmopolitan city of Rome, while there is evidence of a Latin translation of the Bible in the 2nd century (see also Vetus Latina) in southern Gaul and the Roman province of Africa.
With the decline of the Roman Empire, distinctions appeared also in organization, since the bishops in the West were not dependent on the Emperor in Constantinople and did not come under the influence of the Caesaropapism in the Eastern Church. While the see of Constantinople became dominant throughout the Emperor's lands, the West looked exclusively to the see of Rome, which in the East was seen as that of one of the five patriarchs of the Pentarchy, "the proposed government of universal Christendom by five patriarchal sees under the auspices of a single universal empire. Formulated in the legislation of the emperor Justinian I (527–565), especially in his Novella 131, the theory received formal ecclesiastical sanction at the Council in Trullo (692), which ranked the five sees as Rome, Constantinople, Alexandria, Antioch, and Jerusalem."
Over the centuries, disagreements separated Western Christianity from the various forms of Eastern Christianity: first from East Syrian Christianity after the Council of Ephesus (431), then from that of Oriental Orthodoxy after the Council of Chalcedon (451), and then from Eastern Orthodoxy with the East-West Schism of 1054. With the last-named form of Eastern Christianity, reunion agreements were signed at the Second Council of Lyon and the Council of Florence, but these proved ineffective.