Qajar Dynast Agha Mohammad Khan The Qajars were a Turkmen tribe that held ancestral lands in present-day Azerbaijan, which then was part of Iran. In 1779, following the death of Mohammad Karim Khan Zand, the Zand Dynasty ruler of southern Iran, Agha Mohammad Khan, a leader of the Qajar tribe, set out to reunify Iran. Agha Mohammad Khan defeated numerous rivals and brought all of Iran under his rule, establishing the Qajar dynasty. By 1794 he had eliminated all his rivals, including Lotf 'Ali Khan, the last of the Zand dynasty, and had reasserted Iranian sovereignty over the former Iranian territories in Georgia and the Caucasus. Agha Mohammad established his capital at Tehran, a village near the ruins of the ancient city of Ray (now Shahr-e Rey). In 1796 he was formally crowned as shah. Agha Mohammad was assassinated in 1797 and was succeeded by his nephew, Fath Ali Shah.
Fath Ali Shah, 1797 - 183 Under Fath Ali Shah, Iran went to war against Russia, which was expanding from the north into the Caucasus Mountains, an area of historic Iranian interest and influence. Iran suffered major military defeats during the war. Under the terms of the Treaty of Golestan in 1813, Iran recognized Russia's annexation of Georgia and ceded to Russia most of the north Caucasus region. A second war with Russia in the 1820s ended even more disastrously for Iran, which in 1828 was forced to sign the Treaty of Turkmanchai acknowledging Russian sovereignty over the entire area north of the Aras River (territory comprising present-day Armenia and Republic of Azerbaijan).
Fath Ali's reign saw increased diplomatic contacts with the West and the beginning of intense European diplomatic rivalries over Iran. His grandson Mohammad Shah, who fell under the influence of Russia and made two unsuccessful attempts to capture Herat, succeeded him in 1834. When Mohammad Shah died in 1848 the succession passed to his son Naser-e-Din, who proved to be the ablest and most successful of the Qajar sovereigns. Naser o-Din Shah Naser o-Din Shah, 1848 - 189 During Naser o-Din Shah's reign Western science, technology, and educational methods were introduced into Iran and the country's modernization was begun. Naser o-Din Shah tried to exploit the mutual distrust between Great Britain and Russia to preserve Iran's independence, but foreign interference and territorial encroachment increased under his rule. He contracted huge foreign loans to finance expensive personal trips to Europe. He was not able to prevent Britain and Russia from encroaching into regions of traditional Iranian influence. In 1856 Britain prevented Iran from reasserting control over Herat, which had been part of Iran in Safavid times but had been under non-Iranian rule since the mid-18th century. Britain supported the city's incorporation into Afghanistan; a country Britain helped create in order to extend eastward the buffer between its Indian territories and Russia's expanding empire. Britain also extended its control to other areas of the Persian Gulf during the 19th century. Meanwhile, by 1881 Russia had completed its conquest of present-day Turkmenistan and Uzbekistan, bringing Russia's frontier to Iran's northeastern borders and severing historic Iranian ties to the cities of Bukhara and Samarqand. Several trade concessions by the Iranian government put economic affairs largely under British control. By the late 19th century, many Iranians believed that their rulers were beholden to foreign interests.