Saint Thomas Aquinas was well known building a bridge between philosophy and theology. Although having Platonic influences, Aquinas was mainly an Aristotelian. He mixed his Aristotelian philosophy with the Christian theology (p.163). Aquinas tackles the subjects of Gods existence, creation, morality, and human nature.
St. Thomas approaches the topic on the existence of God with a philosophical approach. Instead of assuming that God exists and then finding proof, he comes up with reasons that result in the existence of God by using five different points. His first three points infer that motion proves God's existence. His fourth explanation is based on perfection, and the fifth is based on the idea of a necessary being (p.169-171).
In explaining creation, Aquinas combines a philosophical and theological view. The philosophical view says that the world had always existed. The theological view said that God decided to create the world at some point in time. Aquinas smashes these to ideas to form a new one. He says that God did create, but he created in eternity. This satisfies both sides because it does not contradict itself (p.173-174).
Aquinas had strongly taken an Aristotelian view in explaining morality. He says that morality is based on will, but will is not everything. You must have intellect in order for will to work correctly. The intellect serves as a guide to will to choose what is right. He also adds that an act is not human if it is not free. Therefore if you were forced to do something wrong, it would not be considered morally wrong because you were not able to make a choice (p.176-177).
Finally, Thomas felt that human nature consisted of the body and soul being one. They had both depended on one another. The body needs the soul for form, while the soul required the body for its senses in order to obtain knowledge. He also believed that angels did not have bodies because they were pure knowledge.