Pope John II (born Mercurius) was pope from 533 to 535.
He was the son of a certain Projectus, born in Rome and a priest of the Basilica di San Clemente on the Caelian Hill. He was made pope January 2 533. The basilica of St. Clement still retains several memorials of "Johannes surnamed Mercurius". Presbyter Mercurius is found on a fragment of an ancient ciborium, and several of the marble slabs which enclose the schola cantorum bear upon them, in the style of the sixth century, the monogram of Johannes.
At this period simony (the purchase or sale of church offices or preferment) in the election of popes and bishops was rife among clergy and laity. During the sede vacante of over two months, "shameless trafficking in sacred things was indulged in. Even sacred vessels were exposed for sale". The matter had been brought before the Senate, and laid before the Arian Ostrogothic Court at Ravenna. The last decree (Senatus Consultum) which the Roman Senate is known to have issued, passed under Boniface II, was directed against simony in papal elections. The decree was confirmed by Athalaric, king of the Ostrogoths. He ordered it to be engraved on marble, and to be placed in the atrium of St. Peter's (533). By one of Athalaric's own additions to the decree, it was decided, that if a disputed election was carried before the Gothic officials of Ravenna by the Roman clergy and people, three thousand solidi would have to be paid into court. This sum was to be given to the poor. John remained on good terms with Athalaric, who, being of the Arian Christianity, was content to refer to John's tribunal all actions brought against the Roman clergy.
The Liber Pontificalis records that the following year John obtained valuable gifts as well as a profession of orthodox faith from the Byzantine emperor Justinian I the Great, a significant accomplishment in light of the strength of Monophysitism in the Byzantine Empire at that time.
The notorious adulterous behavior of Contumeliosus, Bishop of Riez in Provence, caused John to order the bishops of Gaul to confine him in a monastery; until a new bishop should be appointed, he bade the clergy of Riez obey the Bishop of Arles.
Two hundred and seventeen bishops assembled in a council at Carthage (535) submitted to John II whether bishops who had lapsed into Arianism should, on repentance keep their rank or be admitted only to lay communion. The question of readmittance to the lapsed troubled north Africa for centuries: see Novatianism and Donatism. The answer to their question was given by Agapetus, as John II died May 8 535. He was buried in St Peter's Basilica.