Ayatollah is an honorific title for high-ranking Twelver Shia clergy in Iran that came into widespread usage in the 20th century. It is not a specific person or position, but rather a title of respect for a religious leader among Shiite Muslims. The most well-known ayatollah is likely Ayatollah Ali Khamenei, who is the second and current supreme leader of Iran. As supreme leader, Khamenei is the most powerful political authority in the Islamic Republic. He is the head of state of Iran, the commander-in-chief of its armed forces, and can issue decrees and make the final decisions on the main policies of the government in many fields such as economy, the environment, foreign policy, and national planning in Iran.