Yet science as an organized, sustained enterprise arose only once in human history. And where did it arise? In Europe, in the civilization then called Christendom. Why did modern science develop here and nowhere else? In his September 12, 2006, speech in Regensburg, Germany, Pope Benedict XVI argued that it was due to Christianity’s emphasis on the importance of reason. The pope argued that reason is a central distinguishing feature of Christianity. While the Regensburg address became controversial because of the pope’s remarks about Islam, on his point about Christianity and reason he was right. An unbiased look at the history of science shows that modernscience is an invention of medieval Christianity, and that the greatest breakthroughs in scientific reason have largely been the work of Christians. Even atheist scientists work with Christian assumptions that, due to their ignorance of theology and history, are invisible to them.