Pope Stephen IV

Pope Stephen IV (Latin: Stephanus IV; died 24 January 817) was the bishop of Rome and leader of the Papal States from June 816 to his death on 24 January 817. Stephen belonged to a noble Roman family. In October 816, he crowned Louis the Pious as emperor at Reims, and persuaded him to release some Roman political prisoners he held in custody. He returned to Rome, by way of Ravenna, sometime in November and died the following January.

Source: Wikipedia — https://en.wikipedia.org/wiki/Pope_Stephen_IV