An investigation of the reasons for Mohammad Shah Qajar's defeat in returning the sovereignty of Iran to Herat (1835 - 1839)

The ruler of Herat`s refusal to do fulfill his obligations such as paying the annual tribute، attacking Khorasan trying to occupy Sistan were among the factors that made Mohammad Shah campaign in Herat to not only punish Kamran Mirza but also conquer this city that was once about to be opened by him during his father`s life. At that time، from one side، Russia was trying to encourage the Qajar king to attack Herat and occupy it in order to extend its penetration to Central Asia and Afghanistan. Furthermore، from the other side، Britain was to prevent Mohammad Shah from campaigning in Herat and took advantage of the city as an obstacle against probable attacks of Iran and Russia to India. Finally، while the army of Mohammad Shah was going toward Herat to capture the city، the menaces of Macnille and the navy of Britain to Khark Island and the South of Iran forced the Qajar king to end the siege of Herat without fulfilling his goals. The author، through a descriptive-analytical approach، aims not only at mentioning the reasons for and results of Mohammad Shah`s campaign in Herat but also at figuring out the reasons of his defeat in returning the sovereignty of Iran to the city.