the foundation of ancient Greek learning and science in the Middle Ages, as it had been elaborated and further developed by Roman/Byzantine science and medieval Islamic science. Some scholars have noted a direct tie between "particular aspects of traditional Christianity" and the rise of science. The "Aristotelian tradition" was still an important intellectual framework in the 17th century, although by that time natural philosophers had moved away from much of it. Key scientific ideas dating back to classical antiquity had changed drastically over the years and in many cases had been discredited. The ideas that remained, which were transformed fundamentally during the Scientific Revolution, include: Aristotle's cosmology that placed the Earth at the center of a spherical hierarchic cosmos. The terrestrial and celestial regions were made up of different elements which had different kinds of natural movement. The terrestrial region, according to Aristotle, consisted of concentric spheres of the four classical elements—earth, water, air, and fire. All bodies naturally moved in straight lines until they reached the sphere appropriate to their elemental composition—their natural place. All other terrestrial motions were non-natural, or violent. The celestial region was made up of the fifth element, aether, which was unchanging and moved naturally with uniform circular motion. In the Aristotelian tradition, astronomical theories sought to explain the observed irregular motion of celestial objects through the combined effects of multiple uniform circular motions. The Ptolemaic model of planetary motion: based on the geometrical model of Eudoxus of Cnidus, Ptolemy's Almagest, demonstrated that calculations could compute the exact positions of the Sun, Moon, stars, and planets in the future and in the past, and showed how these computational models were derived from astronomical observations. As such they formed the model for later astronomical developments. The physical basis for Ptolemaic models invoked layers of spherical shells, though the most complex models were inconsistent with this physical explanation. Ancient precedent existed for alternative theories and developments which prefigured later discoveries in the area of physics and mechanics; but in light of the limited number of works to survive translation in a period when many books were lost to warfare, such developments remained obscure for centuries and are traditionally held to have had little effect on the re-discovery of such phenomena; whereas the invention of the printing press made the wide dissemination of such incremental advances of knowledge commonplace. Meanwhile, however, significant progress in geometry, mathematics, and astronomy