The title rabbi (lit., my master) first appeared in ancient Palestine around the first century of the Common Era too designate an individual of exceptional learning and expertise in Jewish law. The term rav (lit., master) emerged several centuries later in Babylonia to distinguish a learned sage consecrated by his mastery of the Torah. The professional rabbinate, however, became visible only in medieval times, although the precise origin and development of this new and distinctive communal institution remain somewhat obscure.