What is the title for a monarch in Iran, particularly during the Safavid and Qajar dynasties?

The title "Shah" used in Iran during the Safavid and Qajar dynasties signifies a king or monarch, representing the highest authority in the monarchy. This title has its roots in the Persian language and has been historically associated with Persian rulers. The Safavid dynasty, which ruled from the early 16th century to the 18th century, is notable for establishing Twelver Shi'ism as the state religion and expanding the Iranian state, while the Qajar dynasty followed and further modernized the concept of kingship in Iran.

In contrast, the other terms listed have different cultural and historical connotations. "Sultan" is typically used in Islamic empires, particularly in the Ottoman Empire, and denotes a ruler with sovereign authority but does not apply to the Iranian context as directly as "Shah." "Emir" connotes a leader or commander in various Islamic societies, usually at a lower rank than a king, and "Viceroy" is a title used primarily in colonial contexts to denote a representative of a monarch in a province or colony, which does not pertain to the indigenous Iranian rule during those dynasties. Thus, the title "Shah" distinctly reflects the appropriate monarchical context of Iran