During 1838, there were rumors in London of a coming Russian move towards Khiva. Additionally, Persia intended to annex Herat to make up for territory it had lost in the Russo-Persian War (1826–28), however the allegiance of Herat to Afghanistan was crucial to the British strategy. The Siege of Herat began in November 1837 when the new Shah of Persia, Mohammed Mirza, arrived before Herat. His intention was to take Herat then move on to Kandahar. With him was the Russian Envoy Count Simonich, seconded Russian officers and a regiment of Russian deserters under the Polish general Berowski. Eldred Pottinger, an officer of the Bengal Artillery, who had earlier entered Herat in disguise, stiffened the defences and despite the presence of Russian advisers the siege lasted eight months. Britain threatened to take military action and Persia withdrew in September.