The historian examines the written records of the past and uses them to study the human societies and interpret the events and trends that shaped them. He can also draw parallels with historical and current events, and sometimes take useful lessons from the outcome of the former. There are many specialties in this broad subject, including art, musicology, politics, specific historical periods, religions, science, social movements, institutions, warfare, and specific regions or cultures. Knowledge of the appropriate languages, both common and obscure, is often a prerequisite for many specialties. In some cases the historian may be one of only a few individuals who can read a forgotten tongue. History differs from Archeology, which uses physical remains to study the past.