Sorry Bob, I should have clarified better! As you say, the Arab/Islam world did indeed save a great deal of ancient wisdom, and added much of their own to it, especially in science and mathematics, and similarly there were some Christian monasteries which DID preserve ancient wisdom, and we are all indebted to them for the accumulated wisdom. However in both of those religions there were less moderate sub-dvisions, and it was these factions of both religions which did a lot of damage. Judaism too has much to answer for over the years. On balance Christianity probably was the worst offender, particularly Catholicism. Interestingly the extreme wings of all 3 main religions of the world are still a threat today, even though they are all founded on many of the same events, people and deities!