Aristotle (384 BC–322 BC) was a Ancient Greek philosopher. Together with Plato and Socrates, Aristotle is one of the most important founding figures in Western philosophy. He was the first to create a comprehensive philosophical system, encompassing morality and aesthetics, logic and science, politics and metaphysics. Aristotle's views on the physical sciences profoundly shaped medieval scholarship, and their influence extended well into the Renaissance.
Aristotle's scientific method had led him to conclude that the Earth was the center of the solar system, with all heavenly objects revolving around it. This idea gained wide acceptance, and was eventually adopted by the Catholic Church, as it supported Scripture.
Thus, Galileo's support for the Copernican view was not only heretical in the view of the Church, but ran contrary to the views of one of the most revered thinkers in Western civilization.