Frankish count and historian whose works, utilizing important sources and official documents, provide an invaluable firsthand account of contemporary events during the reign of the West Frankish king Charles II.

A son of Charlemagne's daughter Bertha and the renowned poet and imperial chancellor Angilbert, Nithard was reared at court. On the death of the emperor Louis I the Pious (840), he became counselor to the youngest of Louis's sons, Charles II the Bald. Failing to prevent a civil war, Nithard fought for Charles in the Battle of Fontenoy (841) against Lothar I, Charles's eldest half brother. In the same year Charles requested that Nithard write an account of recent events. The resulting four-volume Historiae or De dissensionibus filiorum Ludovici pii (“On the Dissensions of the Sons of Louis the Pious”) deals with the discord between the sons of Louis during the years 840–843.

In 843 Charles made Nithard lay abbot of Saint-Riquier, a position he held for only a few months before he died in a battle against the forces of Pippin II of Aquitaine.