Titles of the Shiite clergy in modern historical realities of Iran

The problem of establishment and functioning of the Shiite hierarchical structure in Iran is of the highest relevance, since this institution occupies the leading position in the key national authorities. One can often hear in the media, along with the surname of a religious or political figure, such words as Ayatollah or Hujjat al-Islam, which are indicators of his status in the Shiite hierarchy. However, in reality these terms are of an informal nature and rely more on a historical tradition than on a legally formalized system.