Lord Lytton, the viceroy, ordered a diplomatic mission to set out for Kabul in September 1878 but the mission was turned back as it approached the eastern entrance of the Khyber Pass, triggering the Second Anglo-Afghan War. A British force of about 40,000 fighting men was distributed into military columns which penetrated Afghanistan at three different points. An alarmed Sher Ali attempted to appeal in person to the tsar for assistance, but unable to do so, he returned to Mazari Sharif, where he died on 21 February 1879.