The son of a priest,Marinus was groomed from very early for big things in the Church. Moving to Rome and entering into the Papal court when he was only 12,he worked his way up to be a trusted legate to several Popes. When he became Pope he pardoned several priests and Bishops that had been excommunicated by his predecessor Pope John VIII. One of those Bishops was named Formosus,who will become Pope in 891 and will be a part of the most bizarre scene in Papal history…..but we’ll get to that in three more weeks. (oh boy is it weird…..)
When researching the history of the Papacy,historians often mixed up the names of Pope Marinus and Pope Martinus(or Martin). Popes Marinus II and III were listed as Martins by mistake and so when French Bishop Simon de Brion became Pope in 1281 he took the name Martin IV when he should have been Martin II. File this under useless Papal trivia.