Pope Marinus I was Pope from 16 December 882 to his death in 884.
Background
Born the son of a priest, he was ordained as a deacon by Pope Nicholas I. Before his election as Pope, he served as Bishop of Caere, which made his election controversial, because, at this stage of history, a bishop was expected never to leave office to move to another see.
Career
He succeeded John VIII in about the end of December 882. On three separate occasions he had been employed by the three popes who preceded him as legate to Constantinople, his mission in each case having reference to the controversy started by Photius, Patriarch of Constantinople. Among his first acts as pope were the restitution of Formosus as Cardinal Bishop of Portus and the anathematizing of Photius.
Due to his respect for Alfred the Great (r 871–899), he freed the Anglo-Saxons of Rome from tribute and taxation.
He died in May or June 884, his successor being Adrian III.
Because of the similarity of the names Marinus and Martinus, Popes Marinus I and Marinus II were, in some sources, mistakenly given the name Martinus (and were then listed respectively as Martinus II and Martinus III). Thus, when the new Pope in 1281 took the name Martin, he became Pope Martin IV.