According to Iran Chamber Society, the Iranian government operated as a kingdom before 1900. The country was ruled by the Qajar dynasty, which saw the reign of four shahs during the 18th and 19th centuries.
The Qajar dynasty was formed after Agha Mohammed Khan, leader of the southern Qajar tribe, sought to unify Iran following the death of the Zand dynasty ruler. Mohammaed Khan was assassinated in 1797 and was succeeded by his nephew Fath Ali Shah. A progressive modernization of Iran embracing Western science and technology took place during the subsequent reign of Naser o-Din Shah. In 1896, Mozaffar o-Din Shah encountered huge resistance against his rule, with protests aimed at his excessive spending.