section_path: Religion/Christianity
section_name: Christianity
paragraph_text: Christianity
  
  The first Christian communities began in Judea, in the Roman Empire, in the second quarter of the first century. They swiftly spread into the Jewish diaspora, along the trade and travel routes followed by merchants, soldiers and migrating tribes, moving from fewer than 50,000 adherents to over a million in the hundred years between 150 and 250. Driven by a universalist logic, Christianity has been, from its beginnings, a missionary faith with global aspirations, leading it to become a part of the history of a great many civilizations.
  
  Constantine the Great became the Roman emperor in 306 and issued the Edict of Milan expressing tolerance for all religions in 313. The Edict was a pluralist policy, and throughout the Roman Empire of the fourth to sixth centuries, people chose between a variety of religious groups in a kind of "religious marketplace".
  
  Constantine did not make Christianity the state religion. Law, literature, rituals, and institutions indicate that converting the empire to Christianity was a complex, long-term, slow-paced, and uneven process with no single moment or event to mark Christianity becoming the Roman Empire's state religion. Constantine wrote laws against sacrifice and magic, and laws that favored Christianity, but there was no legislation forcing the conversion of polytheists until the reign of the Eastern Emperor Justinian I in A.D. 529.
  
  In the fourth century, the diverse network of separate churches became an organization that mirrored the structure of the Roman Empire. Often referred to as the "golden age" of patristic Christianity, Christians of this era compiled many of Christianity's greatest works as they transformed and defined its art, culture, literature, philosophy and politics, its internal and external relationships, and its theology.
  
  The Church of this age was seen by its supporters as a universal all-embracing union of separate individual churches. Yet, the tendency for East and West to grow apart was already evident. The western church spoke Latin, while the East spoke, and wrote, in Greek and at least five other languages. The ancient state was a religious institution, yet East and West related to that State differently: the Catholic church condemned Roman culture as sinful, kept itself as separate as possible, and struggled to resist State control. This is in pointed contrast with Eastern Christianity which acclaimed harmony with Greek culture, and whose emperors and Patriarchs upheld unanimity between church and state.
  
  Regional variations led to competing orthodoxies, and conflicts over defining heresy and orthodoxy dominated fourth century Christianity. These ongoing controversies were a large part of what led the Armenian, Assyrian, and Egyptian churches to combine into what is today known as Oriental Orthodoxy, one of three major branches of Eastern Christianity, along with the Church of the East in Persia and Eastern Orthodoxy in Byzantium.
  
  The patriarchs in the East frequently looked to the Pope, the bishop of Rome, to resolve disagreements for them, thereby establishing what would later become important features of papal power and influence. Still, by the end of the sixth century, large sections of both the Western and Eastern church remained unconvinced they should be submissive to the Roman See. The vision of a universal and united Christendom was slowly coming undone.
  
  According to the early Christian expert Tia Kolbaba, the Arab, Lombard, and Slavic invasions contributed to the alienation between the churches of Rome and Constantinople despite their shared past. Disagreement about Constantinople's jurisdiction compared to Rome's intensified as a result. Misunderstandings and conflicts over ritual, such as the use of unleavened bread in the Eucharist, and differences in points of doctrine (such as the Filioque Clause and Nestorianism), as well as differences in religious practices (such as celibacy, and even the growing of beards), underline the increasing separation of their unique social structures and cultures. Theological differences became more pronounced. There was a general lack of charity and respect on both sides. In 1054, the Patriarch of Constantinople refused to submit to the supremacy of the Roman Pope. Eventually, this all led to the East–West Schism, also known as the "Great Schism", which officially separated Christianity into Western Catholicism and Eastern Orthodoxy.
  
  In 1439, a reunion agreement between the Eastern and Western church was proposed. Popular resistance in the East interfered, so it wasn't until 1452 that the decree of union was officially published in Constantinople. The agreement was overthrown the very next year by the Fall of Constantinople to the Ottoman Turks in 1453. The conquest of 1453 destroyed the Orthodox Church as an institution of the Christian empire inaugurated by Constantine, sealing off Greek-speaking Orthodoxy from the West for almost a century and a half. However, the church survived in altered form, and the spiritual and cultural influence of the Eastern church, Constantinople, and Mount Athos the monastic peninsula has continued.