The founders of the Qajar dynasty Agha Mohamad Khan Qajar who were members of a Turkmen tribe, known as Qajars, who had been brought to Iran from Central Asia during the Mongol invasion. Upon the arrival of this tribe, many feudal governors from different parts of the country mutually destroyed each other, either united or finally obeying the king of the country's capital in a federal system. After this unification, the Iranians united under a single banner. Their tribal colors still survived in the Iranian banner.
During the Qajar period, British and Russian colonial powers increased their influence in Iran. They intervened in state affairs and imposed shameful and degrading treaties such as Turkmenchay. The treaties of Golestan and Paris, fighting a weakened Iran, have separated vast territories from Azerbaijan, Georgia, Armenia, Khorassan, and Afghanistan. The Qajar dynasty is famous for its incompetence and lethargy. During their reign, which began in 1781 and continued until 1925, the Iranian economy deteriorated badly. Amir Kabir was one of Iran's most effective prime ministers under Naser al-Din Shah. He was the founder of the Dar-
The constitutional revolution took place during the Qajar dynasty.