The rise of Islam was opportuned by mass death.
http://www.globalterrorism101.com/JustiniansPlague.html
The Hypothetical Effects of a Release of Pneumonic Plague in New York City
"Terrorists release a deadly plague in New York City. In this simulated exercise, terrorists on board a ship from the Middle East, with Liberian registry, are able to successfully and covertly release plague in the form of an aerosol in the New York City Harbor. Three days pass before the first cases of the plague victims beginning reporting to local hospitals and military treatment facilities for care. The intentional release of the plague on a modern metropolitan area would be devastating. Casualties would quickly overwhelm the existing medical system, and initial attempts at quarantine would fail. Panic would ensue, and eventually the world's population, governments and economies maybe impacted. Government and military leaders, reacting to demands of revenge from their populations, would begin military strikes against those countries, correctly or incorrectly assumed responsible for the initial release of the plague. Religious fanaticism would rise as extremists attempt to explain the modern catastrophe as the will of an angered God. The intentional and successful release of the plague by terrorists in a major metropolitan area would significantly alter the existing world society."