Since when he Francis Wallace Grenfell's rank in the British Army been the highest rank?
Francis Grenfell, 1st Baron Grenfell Field Marshal Francis Wallace Grenfell, 1st Baron Grenfell, GCB, GCMG, PC (29 April 1841 – 27 January 1925) was a British Army officer. After serving as aide-de-camp to the Commander-in-Chief, South Africa, he fought in the 9th Xhosa War, the Anglo-Zulu War and then the Anglo-Egyptian War. He went on to become Sirdar (Commander-in-Chief) of the Egyptian Army and commanded the forces at the Battle of Suakin in December 1888 and at the Battle of Toski in August 1889 during the Mahdist War. After that he became Governor of Malta and then Commander-in-Chief, Ireland before retiring in 1908.
Generalissimus of the Soviet Union Generalissimo of the Soviet Union (Russian: Генералиссимус Советского Союза ; "Generalissimus Sovétskogo Soyuza") was a proposed military rank created on 27 June 1945, following the tradition of the Imperial Russian Army. It was granted to Joseph Stalin following World War II; however, Stalin refused to officially approve the rank. It would have been the highest military rank in the Soviet Union.