During the Second Opium War (1857-1860), Nikolay Muravyov-Amursky approached Yishan and offered to provide Russian assistance to the Qing Empire against the British and French, in return for redefining the Sino-Russian border along the Amur and Ussuri rivers. The Russians also put up a display of their military power by firing artillery shells along the Amur River. Yishan was terrified but did not want to retaliate for fear of starting another war. In May 1858, the Russian and Qing Empires signed the Treaty of Aigun, which transferred the lands between the Stanovoy Range and Amur River to the Russian Empire. In 1860, the Russians intervened in the Convention of Beijing (which ended the Second Opium War), and forced the Qing Empire to further cede its territories east of the Ussuri River, including Sakhalin, to them. The Xianfeng Emperor was enraged by the territorial losses to the Russians, so he dismissed Yishan from his office as General of Heilongjiang, despite the latter's attempts to explain himself. Yishan returned to Beijing to await further orders but was soon back into service.