Written from 1265 – 1274, the Summa theologiae, or ‘summary of Theology’, is considered to be St. Thomas Aquinas’ greatest work. Although unfinished – Aquinas died before completing The Third Part – the gigantic work nonetheless attempts to present all of Christian theology as systematically as possible.
Just before Aquinas was nearly finished with the work, he underwent an experience which, according to him, was so intense that it made everything he had written seem like straw. This forced him to completely stop writing, and he died three months later in 1274. He was canonized in 1323.
The Summa theologiae, also subsequently called the Summa theologica or simply the Summa, has since been studied and used by countless people for many centuries. It is intended as a set of “instructions for beginners,” and a sum of all known learning as explained according to the philosophy of Aristotle, Arabian commentators and the theological dicta of the Church.
Throughout the work, Aquinas cites not only the Sacred Scripture and Christian scholars, but also Greek, Roman, Jewish and Muslim scholars. The most famous section of the book is arguably the Quinque viae, Latin for ‘five ways,’ where Aquinas presents five arguments for the existence of God.
The Summa theologiae is divided into three parts, with only the first and second parts wholly the work of Aquinas. Each of these three parts contains numerous subdivisions, with a format of “questions” used throughout.
The First Part of the Summa begins with the existence and nature of God. The very first “question” deals with the nature of Theology itself, with the second relating to God’s existence. From here, the questions – of which there are 119 in total – turn towards the creation of the world, angels, the nature of man and divine government.
The Second Part comprises of 303 questions which deal mainly with morality and law. It includes Aquinas’ account of the theological and cardinal virtues, as well as the seven deadly sins.
The Third Part deals with the Christ and comprises of questions concerning the incarnation, the sacraments and the resurrection. The first 90 questions of this part were completed by Aquinas before his death, with 99 additional questions included in some editions of his work as a Supplement. These deal with a wide variety of loosely related issues.
Taken together, these three parts form what is now widely considered to be one of the most impressive works of Christianity. They present the reasoning for almost all points of Christian theology in the West, and can be relied upon for answers to both a passing inquiry, as well as more serious questions.