Field Marshal Robert Cornelis Napier, 1st Baron Napier of Magdala was a British Indian Army officer. He fought in the First Anglo-Sikh War and the Second Anglo-Sikh War before seeing action as chief engineer during the second relief of Lucknow in March 1858 during the Indian Rebellion of 1857. He also served in the Second Opium War as commander of the 2nd division of the expeditionary force which took part in the Battle of Taku Forts, the surrender of Peking's Anting Gate and the entry to Peking in 1860. He subsequently led the punitive expedition to Abyssinia in July 1867, defeating the Emperor Tewodros II of Ethiopia with minimal loss of life among his own forces and rescuing the hostages of Tewodros.

Field marshal (FM) has been the highest rank in the British Army since 1736. A five-star rank with NATO code OF-10, it is equivalent to an Admiral of the Fleet in the Royal Navy or a Marshal of the Royal Air Force in the Royal Air Force (RAF). A Field Marshal's insignia consists of two crossed batons surrounded by yellow leaves below the Tudor Crown. Like Marshals of the Royal Air Force and Admirals of the Fleet, Field Marshals traditionally remain officers for life, though on half-pay when not in an appointment or retired. The rank has been used sporadically throughout its history, and was vacant during parts of the 18th and 19th centuries. After the Second World War, it became standard practice to appoint the Chief of the Imperial General Staff to the rank on his last day in the post. Army officers occupying the post of Chief of the Defence Staff, the professional head of all the British Armed Forces, were usually promoted to the rank upon their appointment.