The Tanakh describes circumstances in which a person who is "tahor" or ritually pure may become "tamei" or ritually impure. Some of these circumstances are contact with human corpses or graves, seminal flux, vaginal flux, menstruation, and contact with people who have become impure from any of these. In Rabbinic Judaism, Kohanim, members of the hereditary caste that served as priests in the time of the Temple, are mostly restricted from entering grave sites and touching dead bodies. During the Temple period, such priests (Kohanim) were required to eat their bread offering (Terumah) in a state of ritual purity, which laws eventually led to more rigid laws being enacted, such as hand-washing which became a requisite of all Jews before consuming ordinary bread.