教皇不可謬説
Tancred's origins lie in Germany, where, if his hagiographers are to be believed, he was a soldier of middle rank at the court of the Emperor Frederick II. He was educated under John of Wales at the University of Bologna. He wrote an important gloss on the "Compilatio tertia" and the "Summa de matrimonio" (Summary of Marriage), which was influential to Ramon de Penyafort, as well as the "Ordo iudiciarius", completed in 1216, which was the culmination of the procedural literature of the glossators and was translated into both German and French, indicating its importance for medieval legal practice. He supported the emergent doctrine of Papal infallibility and the sect of the Humiliati. He was one of the teachers of Bernard of Botone.