Because it originated as a Jewish sect in the Roman province of Asia Minor and lacked a firm spiritual anchorage at the beginning, Christianity became, from the very start, a missionary religion.
The written fundamentals were developed over many centuries, beginning with the writings of the apostles and evangelists. First, Christianity conquered the eastern provinces of the Roman Empire.
It was believed that God had created the Roman Empire only to provide the conditions for the expansion of Christianity. The administrative organisation, the widespread use of Latin and Greek, the relatively well-developed means of communication by sea and land, and, above all, the cosmopolitan and multi-religious Roman world paved the way for this new religion. However, its success was far from sure.
The religion prevailed, however, initially in the Middle East rather than in Europe. When one considers that Christianity is of Middle Eastern origin, its close relations with Europe are one of the paradoxes of history.
The other paradox is that Christianity has a relatively small impact on present-day societies and cultures in the Middle East. The rise of Islam and the split of the Church into Byzantine, Christian and numerous local Christian religions contributed to this small impact.
There are many other reasons for Christianity’s relative failure to exert a greater influence; the fact remains that the territorial roots of Christianity are about to vanish in large parts of the Middle East. Christianity and Islam were, from the very beginning, not only religions, but also social and cultural movements.
Both religions have common roots in Judaism, share the same religious figures and sites, and are often based on the same stories, legends, dreams, or writings.
The three religions originate from the same region and share the same fragmentation. By the last decades of the sixth century, just before the rise of Islam, Christianity was divided in sentiment, language, cult and organisation.
The Monophysites dominated a vast area extending from Armenia in the north to Ethiopia in the south and including much of Syria, Mesopotamia and the Persian frontier. Chalcedonian orthodoxy prevailed in Palestine, Asia Minor and the Balkan provinces of the Byzantine empire. Copts lived in Egypt.
Nestorians and Arians, actually, there were many Christian worlds and the Roman papacy and Christianity were weak and in an early stage of development. Even in today’s heartland of Christianity, Europe, the differentiation between eastern (Greek) and western (Latin) was evident.
The swift expansion of Islam was mainly due to the fragmentation of Christianity and the vacuum left by the fall of the Roman Empire. After initial successes, Islam shared the fate of Christianity; however, differentiation became the driving force for division.
Almost fifteen hundred years after the rise of Islam, it is still too early to judge the future development of this religion, like nobody predicted the developments in the Christian Church of the past fifty years.
Source: G. Barraclough, The Christian World. A Social and Cultural History of Christianity (London 2003).