◼◼◼◼◼◼◼◼◼ (Arabic: آية الله, romanized: ʾāyatu llāh, lit. 'sign of god') is a title for high-ranking Twelver Shia clergy. It came into widespread usage in the 20th century. Those who hold this title must be men and specialists in Islamic sciences such as jurisprudence (fiqh) and principles (usul), often teaching in seminaries. The next lower rank among these clergy is Hojjatoleslam. Originally used as a title bestowed by popular/clerical acclaim for a small number of the most distinguished marja' at-taqlid mujtahid, it suffered from "inflation" following the 1979 Iranian Revolution when it came to be used for "any established mujtahid". By 2015, it was further expanded to include any student who had passed their Mujtahid final exam, leading to "thousands" of ◼◼◼◼◼◼◼◼◼s. The title is not used by the Sunni community of Iran, as Sunnis do not believe Muhammad designated a divinely appointed successor. In the Western world—particularly after the 1979 Iranian Revolution— it was associated with the Supreme Leader of Iran, especially Iran's first supreme leader Ruhollah Khomeini, who was so well known as to often be referred to as "The ◼◼◼◼◼◼◼◼◼".