Thomas began his greatest undertaking by writing the Summa Theologica. He distanced himself from this work, leaving it unfinished, and began writing commentaries on many of Aristotle's writings. Thomas thought that Aristotle's ideas were important enough to be elaborated and clarified. As a philosopher, Thomas was “emphatically Aristotelian” (McInerny). The Saint adopted many of his ideas from Aristotle and natural philosophy, as seen in the Summa Theologica where the theologian mentions the philosopher almost two hundred times (Aquinas). The Summa Theologica is divided into three main parts: the existence and nature of God, man, and Christ. These topics are further divided into multiple subtopics. St. Thomas shared the belief that religion and reason could coexist. In his writings, St. Thomas demonstrates that God's revelation is not contrary to reason. The Summa Theologica of Thomas inspired many decrees of the Church. Thomas remains one of Christianity's most influential theologians and one of its most significant philosophers. His works are unmatched by any other theologian and are still consulted when the Church makes decisions about the teachings of