He wrote three books on witchcraft, analysing the Sabbath, lycanthropy, and sexual relationships during the Sabbath. According to his opinion, Satan had little sexual intercourse with single women, because he preferred married women for that implied also adultery, and the incest between mothers and sons at the end of the Sabbath was essential to give birth to demonic children, as well as a sexual act between a witch and a he-goat (believed to be Satan present at the reunion). He also thought that Satan was pleased with a clean body but not a clean (or pure) soul, inducing people to wash their body and embellish themselves with ornaments.