How did Anselm of Canterbury combine faith and reason?

St. Anselm of Canterbury, often called the father of Scholasticism, integrated faith and reason by operating under the principle that faith precedes understanding, yet reason serves to illuminate and provide rational support for what is already believed.123

In his view, while faith is the starting point, human intellect is capable of exploring and proving the truths of that faith. This approach is best exemplified by his work Proslogion, originally titled Fides quaerens intellectum ("Faith Seeking Understanding"). Anselm famously demonstrated this by attempting to prove the existence of God using reason alone, without relying on the authority of Scripture.14

His ontological argument posits that because God is defined as the being "than which nothing greater can be conceived," God must exist in reality as well as in the intellect; otherwise, a greater being—one that exists in both—could be conceived. By utilizing Neoplatonic thought and rigorous logic, Anselm established a model where philosophy acted as a "handmaiden" to theology, allowing for a rational interpretation of religious mysteries.513