One thousand years ago, there were almost as many Christians in Asia and Africa as there were in Europe, and yet we tend to think of the Roman Catholic church as being essentially the only church prior to the Protestant Reformation, according to Philip Jenkins in The Lost History of Christianity: The Thousand-Year Golden Age of the Church in the Middle East, Africa and Asia. Churches that were thriving in the Middle Ages have now vanished, almost without trace.
In the year 544 AD, the city of Merv in southern Turkmenistan became a metropolitan see of the Eastern Church, forming a base for mission further East in Asia. By 550 AD numerous monks had reached China, although the first recorded establishment of a mission in China was at Ch’ang-an in 635. The Emperor Taizong was tolerant towards Christianity, but the mission was destroyed in the 9th century when Emperor Wuzong expelled foreign religions. Genghis Khan was no Christian, but he knew a number of Nestorian Christians.
So how did large numbers of apparently vigorous churches disappear? In the Middle East, Africa and parts of Asia, Christianity coexisted peacefully with Islam for many centuries when Islamic rulers were tolerant, but was eradicated when Islamic rulers were less tolerant. Much of the church in the Middle East was wiped out in the early part of the 20th century.
There is certainly plenty of interesting information in the book. However, a lot of the text seems to be the subjective views of the author rather than a recounting of historical occurrences. The chapters are not arranged chronologically, so the exact sequence of events is not easy to follow. This is not amongst the most engaging history books that I have read, but it certainly has aroused my interest in medieval church history.