East–West Schism in the context of "Christian world"

The Western world, also known as the West, primarily refers to various nations and states in Western Europe, Northern America, and Australasia; with some debate as to whether those in Eastern Europe and Latin America also constitute the West. The Western world likewise is called the Occident (from Latin occidens 'setting down, sunset, west') in contrast to the Eastern world known as the Orient (from Latin oriens 'origin, sunrise, east'). Definitions of the "Western world" vary according to context and perspectives; the West is an evolving concept made up of cultural, political, and economic synergy among diverse groups of people, and not a rigid region with fixed borders and members.

Some historians contend that a linear development of the West can be traced from Ancient Greece and Rome, while others argue that such a projection constructs a false genealogy. A geographical concept of the West started to take shape in the 4th century CE when Constantine, the first Christian Roman emperor, divided the Roman Empire between the Greek East and Latin West. The East Roman Empire, later called the Byzantine Empire, continued for a millennium, while the West Roman Empire lasted for only about a century and a half. Significant theological and ecclesiastical differences led Western Europeans to consider the Christians in the Byzantine Empire as heretics. In 1054 CE, when the church in Rome excommunicated the patriarch of Byzantium, the politico-religious division between the Western church and Eastern church culminated in the Great Schism or the East–West Schism. Even though friendly relations continued between the two parts of Christendom for some time, the crusades made the schism definitive with hostility. The West during these crusades tried to capture trade routes to the East and failed, it instead discovered the Americas. In the aftermath of the European colonization of the Americas, primarily involving Western European powers, an idea of the "Western" world, as an inheritor of Latin Christendom emerged. According to the Oxford English Dictionary, the earliest reference to the term "Western world" was from 1586, found in the writings of William Warner.

The history of Rome includes the history of the city of Rome as well as the civilisation of ancient Rome. Roman history has been influential on the modern world, especially in the history of the Catholic Church, and Roman law has influenced many modern legal systems. Roman history can be divided into the following periods:

• Pre-historical and early Rome, covering Rome's earliest inhabitants and the legend of its founding by Romulus
• The period of Etruscan dominance and the regal period, in which, according to tradition, Romulus was the first of seven kings
• The Roman Republic, which commenced in 509 BC when kings were replaced with rule by elected magistrates. The period was marked by vast expansion of Roman territory. During the 5th century BC, Rome gained regional dominance in Latium. With the Punic Wars from 264 to 146 BC, ancient Rome gained dominance over the Western Mediterranean, displacing Carthage as the dominant regional power.
• The Roman Empire followed the Republic, which waned with the rise of Julius Caesar, and by all measures concluded after a period of civil war and the victory of Caesar's adopted son, Octavian, in 27 BC over Mark Antony.
• The Western Roman Empire collapsed in 476 after the city was conquered by the Ostrogothic Kingdom. Consequently, Rome's power declined, and it eventually became part of the Eastern Roman Empire, as the Duchy of Rome, from the 6th to 8th centuries. At this time, the city was reduced to a fraction of its former size, being sacked several times in the 5th to 6th centuries, even temporarily depopulated entirely.
• Medieval Rome is characterised by a break with Constantinople and the formation of the Papal States. The Papacy struggled to retain influence in the emerging Holy Roman Empire, and during the saeculum obscurum, the population of Rome fell to as low as 30,000 inhabitants. Following the East–West Schism and the limited success in the Investiture Controversy, the Papacy did gain considerable influence in the High Middle Ages, but with the Avignon Papacy and the Western Schism, the city of Rome was reduced to irrelevance, its population falling below 20,000. Rome's decline into complete irrelevance during the medieval period, with the associated lack of construction activity, assured the survival of very significant ancient Roman material remains in the centre of the city, some abandoned and others continuing in use.
• The Roman Renaissance occurred in the 15th century, when Rome replaced Florence as the centre of artistic and cultural influence. The Roman Renaissance was cut short abruptly with the devastation of the city in 1527, but the Papacy reasserted itself in the Counter-Reformation, and the city continued to flourish during the early modern period. Rome was annexed by Napoleon and was part of the First French Empire from 1809 to 1814.
• Modern history, the period from the 19th century to the present. Rome came under siege again after the Allied invasion of Italy and was bombed several times. It was declared an open city on 14 August 1943. Rome became the capital of the Italian Republic (established in 1946). With a population of 4.4 million (as of 2015; 2.9 million within city limits), it is the largest city in Italy. It is among the largest urban areas of the European Union and classified as a global city.

Greek East and Latin West are terms used to distinguish between the two parts of the Greco-Roman world and of Medieval Christendom, specifically the eastern regions where Greek was the lingua franca and the western parts where Latin filled this role.

Greek had spread as a result of previous Hellenization, whereas Latin was the official administrative language of the Roman state, stimulating Romanization. In the east, where both languages co-existed within the Roman administration for several centuries, the use of Latin ultimately declined as the role of Greek was further encouraged by administrative changes in the empire's structure between the 3rd and 7th centuries, which led to the split between the Eastern Roman Empire and the Western Roman Empire, the collapse of the latter, and failed attempts to restore unity by the former. This Greek–Latin divide continued with the East–West Schism of the Christian world during the Early Middle Ages.

Christendom or the Christian world are terms commonly used to refer to the global Christian community, Christian states, Christian-majority countries or countries in which Christianity is dominant or prevails.

Following the spread of Christianity from the Levant to Europe and North Africa during the early Roman Empire, Christendom has been divided in the pre-existing Greek East and Latin West. After the Great schism of 1054, two main branches within Christianity emerged, centred around the cities of Rome (Western Christianity, whose community was called Western or Latin Christendom) and Constantinople (Eastern Christianity, whose community was called Eastern Christendom or Byzantine commonwealth). After the fall of Constantinople in 1453, Latin Christendom rose to a central role in the Western world. Following the reformation, protestantism emerged as the third main branch of Christianity in the 16th century. The history of the Christian world spans about 2,000 years and includes a variety of socio-political developments, as well as advancements in the arts, architecture, literature, science, philosophy, politics and technology.

Christianity in Italy has been historically characterised by the dominance of the Catholic Church since the East–West Schism. However, the country is also home to significant Christian minorities, especially Orthodox Christians, Protestants and Jehovah's Witnesses.

The country's patron saints are Francis of Assisi and Catherine of Siena.

The Slavs were Christianized in waves from the 7th to 12th century, though the process of replacing old Slavic religious practices began as early as the 6th century. Generally speaking, the monarchs of the South Slavs adopted Christianity in the 9th century, the East Slavs in the 10th, and the West Slavs between the 9th and 12th century. Saints Cyril and Methodius (fl. 860–885) are attributed as "Apostles to the Slavs", having introduced the Byzantine-Slavic rite (Old Slavonic liturgy) and Glagolitic alphabet, the oldest known Slavic alphabet and basis for the Early Cyrillic alphabet.

The simultaneous missionary efforts to convert the Slavs by what would later become known as the Catholic Church of Rome and the Eastern Orthodox Church of Constantinople led to a 'second point of contention between Rome and Constantinople', especially in Bulgaria (9th–10th century). This was one of many events that preceded the East–West Schism of 1054 and led to the eventual split between the Greek East and Latin West. The Slavs thus became divided between Eastern Orthodoxy and Roman Catholicism. Closely connected to the competing missionary efforts of the Roman Church and the Byzantine Church was the spread of the Latin and Cyrillic scripts in Eastern Europe. The majority of Orthodox Slavs adopted Cyrillic, while most Catholic Slavs adopted the Latin, but there were many exceptions to this general rule. In areas where both Churches were proselytising to pagan Europeans, such as the Grand Duchy of Lithuania, the Croatian Duchy and the Principality of Serbia, mixtures of languages, scripts and alphabets emerged, and the lines between Latin Catholic (Latinitas) and Cyrillic Orthodox literacy (Slavia Orthodoxa) were blurred.