An Ayatollah is a high-ranking Twelver Shia Muslim cleric in Iran who has demonstrated highly advanced knowledge of Islamic law and religion. The title is an honorific and is not used by the Sunni community of Iran, nor by Shias in Lebanon, Pakistan, or India. The title of Ayatollah has been in widespread usage in Iran since the 20th century. The term is often associated with Ruhollah Khomeini, who was a prominent Ayatollah and the founder of the Islamic Republic of Iran.