Rue is also a common ingredient in witchcraft and spell making. During the Middle Ages it was a symbol of recognition between witches. The Catholic Church also used a branch of rue to sprinkle holy water on its followers: during this time it was known as the "herb of grace." Hasidic Jews also were taught that rue should be placed into amulets to protect them from epidemics and plagues. This was taught by Rabbi Isaac of Komarno in his comments to "Sefer Adam Yashar" in the name of Rabbi Isaac Luria.