Prothero was born in
Wiltshire to
George Prothero, and was educated at
Eton, studying classics at
King's College, Cambridge, and at the
University of Bonn. He went on to become a
Fellow of King's College, working as a history
lecturer there from 1876. After five years as Professor of Modern History in Edinburgh, Prothero moved to London to take the place of his brother,
Lord Ernle, as the editor of the
Quarterly Review, a political
periodical. He also acted as editor of the
Cambridge Historical Series, a set of historical books detailing the history of several European nations and other parts of the world which were published by Cambridge University Press from 1894 onwards. With
A. W. Ward and
Stanley Mordaunt Leathes he edited the
Cambridge Modern History between 1901 and 1912. In 1903 he was invited to give the
Rede Lecture, on which occasion he spoke on the topic of
Napoleon III and the
Second French Empire. In 1904–1906 he was a member of the
Royal Commission for Ecclesiastical Discipline. Following the outbreak of
World War I, Prothero worked as Historical Advisor to the
Foreign Office, and in this capacity attended the
Paris Peace Conference of 1919. For his services to the war effort, he was created Knight Commander of the Order of the British Empire in the
1920 New Year Honours. He was married to Fanny (née Butcher), one of the 12 members of the Cambridge
Ladies Dining Society. He died in 1922. ==Selected publications==