Coming from East France, Halphen family lives in Paris and Versailles. An officer and eminent mathematician, the father dies prematurely, as three of his sons, two of whom being fallen in war. Differing from surroundings which were turned to exact sciences, the historian whom family means have allowed to delay the beginning in profession, has largely published since 1901, when he is 1910 appointed to Bordeaux university. Turning his work from thorough investigation of first Capetians and Carolingian times documents, he accepts, with his colleague Sagnac, to edit a series of 20 volumes of universal history, writing alone two of the three which are assigned to the Middle Ages. Turned to Paris in 1928, he gets honors as a reward for his activities, but he is threatened by Anti-Semitism from 1940 and takes refuge from 1941 to 1943 in Grenoble university, in an area which Germans do not yet occupy, before to be bound to hide. These pains do not hinder the writing of an important book on Charlemagne but they hasten his death.