Western Christianity consists of the Latin Church of the Catholic Church, and a variety of Protestant denominations. The name has been applied in order to distinguish these from Eastern Christianity.
Western Christianity initially developed in Europe and Northwest Africa during the first centuries A.D., and later also came to predominate in Southern Africa, throughout Australia, and the Western Hemisphere. Thus, when used for historical periods since the 16th century, the term "Western Christianity" often refers collectively to the Catholic Church and the Protestant denominations combined, especially to their shared theological, doctrinal, and liturgical traits, rather than to their differences.
Today, the geographical distinction between Western and Eastern Christianity is not nearly as absolute, due to the spread of missionary activities, migrations, and general globalisation. The adjectives "Western Christianity" and "Eastern Christianity" are thus typically used to refer to historical origins rather than present geographical locations.
For most of its history the church in Europe has been 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 or indirectly, 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 Though the first Christians in the West used Greek (such as Clement of Rome), by the fourth century Latin had superseded it even in the cosmopolitan city of Rome, while there is evidence of a Latin translation of the Bible in the 2nd century (see also Vetus Latina) in southern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.
The rise of Protestantism led to major divisions within Western Christianity, which still persist, and wars—for example, the Anglo-Spanish War of 1585–1604 had religious as well as economic causes.
In and after the Age of Discovery, Europeans spread Western Christianity to the New World and elsewhere. Roman Catholicism came to the Americas (especially South America), Africa, Asia, Australia and the Pacific. Protestantism, including Anglicanism, came to North America, Australia-Pacific and some African locales.
Today, the geographical distinction between Western and Eastern Christianity is now much less absolute, due to the great migrations of Europeans across the globe, as well as the work of missionaries worldwide over the past five centuries.
Although "original sin" can be taken to mean the sin that Adam committed, it is usually understood as a consequence of the first sin, the hereditary stain with which we are born on account of our origin or descent from Adam. With the exception of tendencies such as Pelagianism, Western Christianity is thought to hold this doctrine, which was championed especially by Saint Augustine, who wrote: "The deliberate sin of the first man is the cause of original sin" (De nupt. et concup., II, xxvi, 43).
Most Western Christians use a version of the Nicene Creed that states that the Holy Spirit "proceeds from the Father and the Son", where the original text as adopted by the First Council of Constantinople had "proceeds from the Father" without the addition of either "and the Son" or "alone". This Western version also has the additional phrase "God from God" (in Latin Deum de Deo), which was in the Creed as adopted by the First Council of Nicaea, but which was dropped by the First Council of Constantinople.
The date of Easter usually differs between Eastern and Western Christianity, because the calculations are based on the Julian calendar and Gregorian calendar respectively. However, the date of observance of Easter has only differed within Christendom (in modern times) since the promulgation of the Gregorian calendar in 1582; and further, the Western Church did not universally adopt the Gregorian calendar at once, so that for some time the dates of Easter differed as between the Eastern Church and the Roman Catholic Church, but not necessarily as between the Eastern Church and the Western Protestant churches. For example, the Church of England continued to observe Easter on the same date as the Eastern Church until 1753.
Even the dates of other Christian holidays differ between Eastern and Western Christianity.
Western Christianity makes up about 90% of Christians worldwide, with the Roman Catholic Church accounting for over half and various Protestant denominations making up another 40%. Hussite movements of 15th century Bohemia preceded the main Protestant uprising by 100 years and evolved into several small Protestant churches, such as the Moravian Church. Waldensians survived also, but blended into the Reformed tradition.