University of Naples, 6 December 1273. A Dominican friar and scholar is working on the final section of his life's culminating work. He is about 48 years old, and has written many biblical and philosophical commentaries and theological treatises. He goes to celebrate mass, and there he experiences a crisis – a mystical experience, or possibly a stroke. "All I have written seems as straw compared to what I have experienced," he says, and he abandons his masterpiece unfinished. A few months later, he falls ill on a journey to a church council in Lyons, and he dies at the monastery at Fossanova on 7 March 1274. The man is Thomas d'Aquino, known to us as Aquinas, and the work is his Summa Theologiae. The 13th century was a turbulent era of crusades, religious conflicts and power struggles. Two of Aquinas's brothers were caught up in wars between Emperor Frederick II and the papacy, and one was executed for treason. Wars were fought in the name of religion, such