British historian of English and Dutch Art. Armstrong was the son of Walter Armstrong, a merchant, and his wife, Mary Graham (Armstrong). He was initially educated at the Harrow School, later graduating from Exeter College, Oxford. Armstrong married Jane Emily Rose Ferard of Ascot Place in 1873. In 1880, Armstrong distinguished himself as an art critic, writing for various papers, like Pall Mall Gazette, St. James's Gazette, Manchester Guardian, and The Examiner.