Christianity Today: But what about the old saying, “The blood of the martyrs is the seed of the church”?
Historian Philip Jenkins: That was said by Tertullian, who came from the church in North Africa, where the church vanished. If you were to look at the healthiest part of Christianity right around the year 400 or 500, you might well look at North Africa, roughly what we call Tunisia and Algeria. It was the land of Augustine. Then the Arabs, the Muslims, arrive. They conquer Carthage in a.d. 698, and 100 years later—I don’t say there were no Christians there, but there certainly was only a tiny, tiny number. That church dies.
The rest is here: http://www.christianitytoday.com/ct/2009/march/24.52.html
It was indeed an interesting and sobering article.
However, I think we must resist the temptation to equate numbers of professing Christians with the spiritual health of the church. I think of the contrast between the church in Philadelphia which had little earthly power but had kept the faith (Rev. 3:8) and the church at Sardis which had the reputation of being alive but was, in fact, dead (Rev. 3:1b).
Agreed. Interpreting accurately all of the relevant details is really only the domain of one Person!