Lawrence Stone said the Elizabethan age was "the greatest age of religious difference before the 20th century." Even today the debate between the moderns and the ancients continues to question the concept of God as occult because there is no scientific proof of his existence. During Faustus' time there were an estimated 900,000 atheists in a population of four to five million, although the estimate was made by a Spanish ambassador. Puritans felt that even the litany was a "conjuring" of God and the Pope and priests were magicians. Modern magic possibly dates from the publishing of Giambattista della Porta's Natural Magic in 1558. Nature was thought to be a secondary cause of occurences, God always being the first cause. The study of Nature bypassed God, causing suspicion of atheism. Magic changed from medieval times when magicians tried to stop or reverse natural processes and began a more scientific approach of finding ways to work in harmony with Nature. Many students of traditional academia turned to scientific research during Marlowe's time as a student at Cambridge. Sir Walter Raleigh typified the 'new man,' whose pursuit for knowledge included both the rational and the occult. Faustus recognizes Hell and the Devil's personal pervasiveness, and he wants the powers of Nature even with its limitations.