Pope Marinus II (or Martin III), was Pope from 30 October 942 to his death in 946.
Marinus was elevated to the papacy on 30 October 942 through intervention of Alberic II of Spoleto, Prince of the Romans. He concentrated on administrative aspects of the papacy, and sought to reform both the secular and regular clergy. He extended the appointment of Frederick, Archbishop of Mainz as Papal Vicar and Missus dominicus throughout Germany and Francia. Marinus later intervened when the Bishop of Capua seized without authorization a church which had been given to the local Benedictine monks. In fact, throughout his pontificate, Marinus favoured various monasteries, issuing a number of Papal bulls in their favour.
Marinus occupied the palace built by Pope John VII atop the Palatine Hill in the ruins of the Domus Gaiana. He died in May 946 and was succeeded by Agapetus II.
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.