Marcellus II, pope of the Catholic Church (d. 1555)
Pope Marcellus II (Italian: Marcello II; 6 May 1501 – 1 May 1555), born Marcello Cervini degli Spannochi, was Bishop of Rome and hence head of the Catholic Church and at that time ruler of the Papal States from 9 April 1555 until his death 22 days later.

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, and the most recent pope to date with the regnal name "Marcellus".

Cervini was the maternal uncle of Robert Bellarmine. His father, Ricardo Cervini, and Pope Clement VII were personal friends. Cervini served in the household of Cardinal Alessandro Farnese. When Farnese became pope, Cervini served as his secretary and was employed on a number of diplomatic missions. On 10 April, 1555, he was elected to succeed Pope Julius III. He died of a stroke twenty-two days later.