A Turkic tribe in north-east Iran that produced the Qajar dynasty, which ruled Persia (Iran) from 1794 to 1925. The dynasty was established by Agha Muhammad (1742–97), a eunuch who made Tehran his capital and was crowned Shah in 1796. He was succeeded by his nephew Fath Ali Shah (1797–1834), during whose reign Iran was forced to cede the Trans-Caucasian lands to Russia. The constitutional revolution of 1906 established a parliament. Muhammad Ali (1907–09) was deposed for attacking the constitution and after a lengthy regency, Muhammad Ali’s son, Ahmad Shah (1914–25), became the last Qajar ruler, being deposed by an army officer, Reza Shah Pahlavi, in 1925.