The distinguished surname Kohen is a proud sign of an ancient Jewish culture. The surname Kohen is an occupational surname for a priest, and it comes from the Hebrew word kohen. Traditionally, priests were considered to have been members of a hereditary caste, descended from Aaron, the brother of Moses. Not all Jewish bearers of the surname Kohen belong to this caste, however. When many Jews were being forced to join the Russian Army for a term of 25 years, a number of them changed their last name to Kohen, because members of the clergy were exempt from service.