For the long centuries of the Middle Ages (500-1350 AD) the canon of scientific knowledge had experienced little change, and the Catholic Church had preserved acceptance of a system of beliefs based on the teachings of the ancient Greeks and Romans which it had incorporated into religious doctrine. During this period there was little scientific inquiry and experimentation. Rather, students of the sciences simply read the works of the alleged authorities and accepted their word as truth. However, during the Renaissance this doctrinal passivity began to change. The quest to understand the natural world led to the revival of botany and anatomy by thinkers such as Andreas Vesalius during the later sixteenth century.
These scientific observers were surprised to find that their conclusions did not always match up with the accepted truths, and this finding inspired others to delve further into the study of the world around them. Scientific study quickly extended from the earth to the heavens, and Nicolas Copernicus, upon examining the records of the motions of heavenly bodies, soon discarded the old geocentric theory that placed the Earth at the center of the solar system and replaced it with a heliocentric theory in which the Earth was simply one of a number of planets orbiting the sun. Though this scheme seemed to comply better with the astronomical records of the time, Copernicus had little direct evidence to support his claims. Not ready to abandon traditional beliefs, the forces of tradition, in the form of the Church and the mass of Europeans, kept the heliocentric theory from achieving full acceptance. The theory awaited the advancement of mathematics and physics to support its claims.
The wait was not very long. During the early seventeenth century, mathematics experienced a great deal of progress in the form of the development of algebra, trigonometry, the advance of geometry, and the linkage of form and motion with quantifiable numeric values undertaken by Rene Descartes. Armed with these tools, the science of physics began to advance rapidly. During the late sixteenth century Galileo Galilei demonstrated that gravity accelerated all objects toward the Earth at the same rate, and further explored the laws of motion. Other physicists explored the nature of matter, with the greatest advances coming in the understanding of the properties of gases, leading to the invention of the barometer, thermometer, and air pump. Physicists even strove (largely unsuccessfully) to discover the structure of matter on the atomic scale.
One of the first applications of the knowledge gained from the advance of physics was in the realm of biology. The physiology of the human body could now be understood in terms of its mechanical properties, and during the seventeenth century many of the mysteries of the human body disappeared. However, the most notable application of the laws of physics was in the field of astronomy. Johannes Kepler proved the orbits of the planets were elliptical, but was unable to come up with an effective model of the solar system. That was left to Galileo, who in 1630 published his Dialogue on the Two Chief Systems of the World, in which he supported the Copernican, or heliocentric theory of the universe, and denounced the Aristotelian system, which maintained the geocentric theory. Galileo supported his claims with elaborate evidence derived from the study of physics.
Sir Isaac Newton's work was the capstone of this evolving chain of science. He integrated Kepler's laws of planetary motion and Galileo's forays into the laws of gravity into a comprehensive understanding of the organization of the universe according to the law of universal gravitation. Newton's Principia, in which he lays out this comprehensive system of organization and develops the mathematical field of calculus, is seen as the key which unlocked the mysteries of the universe, the climax of the strivings of all of the Scientists of the Scientific Revolution.