Theology conquered, he had plunged into decretals. From the "Master of Sentences," he had passed to the "Capitularies of Charlemagne;" and he had devoured in succession, in his appetite for science, decretals upon decretals, those of Theodore, Bishop of Hispalus; those of Bouchard, Bishop of Worms; those of Yves, Bishop of Chartres; next the decretal of Gratian, which succeeded the capitularies of Charlemagne; then the collection of Gregory IX.; then the Epistle of ~Superspecula~, of Honorius III. He rendered clear and familiar to himself that vast and tumultuous period of civil law and canon law in conflict and at strife with each other, in the chaos of the Middle Ages,--a period which Bishop Theodore opens in 618, and which Pope Gregory closes in 1227.
Decretals digested, he flung himself upon medicine, on the liberal arts. He studied the science of herbs, the science of unguents; he became an expert in fevers and in contusions, in sprains and abcesses. Jacques d' Espars would have received him as a physician; Richard Hellain, as a surgeon. He also passed through all the degrees of licentiate, master, and doctor of arts. He studied the languages, Latin, Greek, Hebrew, a triple sanctuary then very little frequented. His was a veritable fever for acquiring and hoarding, in the matter of science. At the age of eighteen, he had made his way through the four faculties; it seemed to the young man that life had but one sole object: learning.
It was towards this epoch, that the excessive heat of the summer of 1466 caused that grand outburst of the plague which carried off more than forty thousand souls in the vicomty of Paris, and among others, as Jean de Troyes states, "Master Arnoul, astrologer to the king, who was a very fine man, both wise and pleasant." The rumor spread in the University that the Rue Tirechappe was especially devastated by the malady. It was there that Claude's parents resided, in the midst of their fief. The young scholar rushed in great alarm to the paternal mansion. When he entered it, he found that both father and mother had died on the preceding day. A very young brother of his, who was in swaddling clothes, was still alive and crying abandoned in his cradle. This was all that remained to Claude of his family; the young man took the child under his arm and went off in a pensive mood. Up to that moment, he had lived only in science; he now began to live in life.
This catastrophe was a crisis in Claude's existence. Orphaned, the eldest, head of the family at the age of nineteen, he felt himself rudely recalled from the reveries of school to the realities of this world. Then, moved with pity, he was seized with passion and devotion towards that child, his brother; a sweet and strange thing was a human affection to him, who had hitherto loved his books alone.