<P> During and after the Renaissance of the 12th century, Europe experienced an intellectual revitalization, especially with regard to the investigation of the natural world . In the 14th century, however, a series of events that would come to be known as the Crisis of the Late Middle Ages was underway . When the Black Death came, it wiped out so many lives it affected the entire system . It brought a sudden end to the previous period of massive scientific change . The plague killed 25--50% of the people in Europe, especially in the crowded conditions of the towns, where the heart of innovations lay . Recurrences of the plague and other disasters caused a continuing decline of population for a century . </P> <P> The 14th century saw the beginning of the cultural movement of the Renaissance . The rediscovery of ancient texts was accelerated after the Fall of Constantinople, in 1453, when many Byzantine scholars had to seek refuge in the West, particularly Italy . Also, the invention of printing was to have great effect on European society: the facilitated dissemination of the printed word democratized learning and allowed a faster propagation of new ideas . </P> <P> But this initial period is usually seen as one of scientific backwardness . There were no new developments in physics or astronomy, and the reverence for classical sources further enshrined the Aristotelian and Ptolemaic views of the universe . Philosophy lost much of its rigour as the rules of logic and deduction were seen as secondary to intuition and emotion . At the same time, Humanism stressed that nature came to be viewed as an animate spiritual creation that was not governed by laws or mathematics . Science would only be revived later, with such figures as Copernicus, Gerolamo Cardano, Francis Bacon, and Descartes . </P> <P> Alchemy is the study of the transmutation of materials through obscure processes . It is sometimes described as an early form of chemistry . One of the main aims of alchemists was to find a method of creating gold from other substances . A common belief of alchemists was that there is an essential substance from which all other substances formed, and that if you could reduce a substance to this original material, you could then construct it into another substance, like lead to gold . Medieval alchemists worked with two main elements or principles, sulphur and mercury . </P>

How did scientific thinking change during the renaissance