Old Persian Khshayathiya,

title of the kings of Iran, or Persia. When compounded as shāhanshāh, it denotes “king of kings,” or emperor, a title adopted by the 20th-century Pahlavi dynasty in evocation of the ancient Persian “king of kings,” Cyrus II the Great (reigned 559–c. 529 BC). Another related title or form of address is padshāh, or “lord king.” The title shāh was also used in Afghanistan until the overturn of the monarchy in 1973 and has been used by rulers and princelings in other countries of central and southern Asia. Sometimes, as a part of a name, shāh was used by hereditary governors and heads of Ṣūfī orders. The son of a shāh is called a shāhzāda (literally “shāh son”). See also shabunder.