Usuard a French hagiographer of the 9th century, was a monk of Sant-Germain- des-Prés at Paris. He wrote a Martyrology under the countenance of Charles the Bald, which vas first printed at the end of Rudimentum Novitiorum (1475), and afterwards served as the basis of the Martyrologium Romanrim. He died Jan. 8, 876 or 877. See Hoefer, Nov. Biog. Géneralé, s.v.