pandemic swept through Asia and the Middle East and into Europe between 1347 and 1350, and is believed to have killed between a third and two-thirds of Europe's population. During the plague, Clement attributed the plague to divine wrath. But he also sought the opinions of astrologers for an explanation. Johannes de Muris was among the team "of three who drew up a treatise explaining the plague of 1348 by the conjunction of Saturn, Jupiter, and Mars in 1341" Clement VI's physicians advised him that surrounding himself with torches would block the plague. However, he soon became skeptical of this recommendation and stayed in Avignon supervising sick care, burials, and the pastoral care of the dying. He never contracted the disease, even though there was so much death around him that the cities ran out of ground for cemeteries, and he had to consecrate the entire Rhône River so that it could be considered holy ground and bodies could be thrown into it. One of Pope Clement's physicians, Gui de Chauliac, later wrote a book called the Chirurgia magna (1363), in which he correctly distinguished between bubonic and pneumonic plague, based on his own observations of his patients and himself. Perhaps feeling the pressure of mortality, having lost no fewer than six cardinals in the year 1348 alone, Pope Clement VI named a new cardinal on 29 May 1348, his nephew and namesake, Pierre Roger de Beaufort, who was not yet eighteen years old. On 17 December 1350, he added twelve more cardinals, nine of them French and only three from Limoges, including two relatives, Guillaume d'Aigrefeuille and Pierre de Cros. Suspicion fell on the Jews for the plague, and pogroms erupted around Europe. Clement issued two papal bulls in 1348 (6 July and 26 September), the latter named Quamvis Perfidiam, which condemned the violence and said those who blamed the plague on the Jews had been "seduced by that liar, the Devil." He went on to emphasise that "It cannot be true that the Jews, by such a heinous crime, are the cause or occasion of the plague, because through many parts of the world the same plague, by the hidden judgment of God, has afflicted and afflicts the Jews themselves and many other races who have never lived alongside them." He urged clergy to take action to protect Jews as he had done. Pope and Empire Clement continued