His efforts to develop a complete ethnographic record of the Huron has been described as "the longest and most ambitious piece of ethnographic description in all "The Jesuit Relations"". Brébeuf tried to find parallels between the Huron religion and Christianity, so as to facilitate conversion of the Huron to the European religion. Brébeuf was known by the Huron for his apparent shamanistic skills, especially in rainmaking. Despite his efforts to learn their ways, he considered Huron spiritual beliefs to be undeveloped and "foolish delusions"; he was determined to convert them to Christianity. Brébeuf did not enjoy universal popularity with the Huron, as many believed he was a sorcerer. By 1640, nearly half the Huron had died of smallpox and the losses disrupted their society. Many children and elders died. With their loved ones dying before their eyes, many Huron began to listen to the words of Jesuit missionaries who, unaffected by the disease, appeared to be men of great power.