Pope Marcellus II, born Marcello Cervini degli Spannochi,was head of the Catholic Church and ruler of the Papal States from 9 April 1555 until his death 22 days later on 1 May 1555.
He succeeded Pope Julius III. Before his accession as pope he had been Cardinal-Priest of Santa Croce in Gerusalemme. He is the most recent pope to choose to retain his birth name as his regnal name upon his accession, as well as only the second and most recent pope to date to take the name "Marcellus" upon being elected. After his death, it would be 423 years before another pope would choose a name with an ordinal number less than IV (John Paul I).