Because the Jesuit order was formed in 1540 and survived as a vibrant and powerful force until 1773, when it was dissolved in Europe, Jesuit natural philosophers found themselves living in a period of enormous scientific and intellectual change. Founded only three years before the publication of Copernicus's De revolutionibus orbium coelestium, the Jesuits had to confront the new science that was emerging from that landmark treatise. In a real sense, they were caught between two intellectual conceptions of the world: the geocentric Aristotelian world view and the new one taking shape around the heliocentric system of Copernicus and the new discoveries of Tycho Brahe and Galileo. What was the reaction of Jesuit natural philosophers?