Pilgram--I agree but it is not always by the sword. Some places simply change because of changing demographics, like the London mosque in Brick Lane--first a French Huguenot protestant church, then a Methodist church, then a Jewish synagogue and now a mosque serving the Bangladeshi community. Next is probably a Catholic church for Polish immigrants. No swords, just poor immigrants making enough money to move out of the inner city and vacating it for the next wave of poor immigrants.