Benedict III, prior to his election, had a reputation for learning and piety, and elected on the refusal of the initial choice of clergy and people, Hadrian: a group of important people preferred Anastasius. This latter group had Benedict's election disavowed and Anastasius installed. However popular opinion was so strong that Benedict's consecration was allowed. The Emperor Louis II's envoys forced Benedict to handle Anastasius and adherents leniently. The schism helped to weaken the hold of the emperors upon the popes, especially upon their elections.
Benedict intervened in the conflict between the sons of Lothair I (the future Lothair II, Louis II and Charles the Bald) on the latter's death. He was active in other cases and adopted a firm position towards Constantinople.
Aethelwulf of Wessex and his son, the future Alfred the Great visited Rome in Benedict's reign.
Pope Joan is usually placed between the reign of Leo IV and Benedict.