The Siege of Herat (1837-1838) was an unsuccessful attack on the Afghan city of Herat, by the Qajar dynasty of Persia, during the time of the Great Game. The siege ended after neither side gained a clear advantage, the British threatened to take military action and the Russians withdrew their support. Herat was held by Kamran and his vizier Yar Mohammed. The Shah of Persia was Mohammed Shah Qajar. Four Europeans were involved: Sir John McNeill and Eldred Pottinger for the British and Count Simonich and Yan Vitkevich for the Russians.