Summa Theologiae (1265-1274)
St. Thomas Aquinas was born in medieval times in the year 1225 AD and lived until the year 1274 AD. One of his most notable writings was Summa Theologiae, which is unfinished. In Summa Theologiae, St. Aquinas discusses several aspects of the Catholic Church such as the Holy Trinity. St. Thomas Aquinas quoted St. Augustine of Hippo several times in the Summa. The Summa was referenced by other saints in their writings and is still used by scholars today. St. Thomas Aquinas's Summa Theologiae is one of the most important works in Church history because of the truth, validity, and genius of his arguments, explanations, and teachings in his masterpiece.