Mercurius, a Roman priest, was elected Pope John II; he was likely the first pope to adopt a new name upon elevation to the papacy. Pope John II: Pope John II, born Mercurius, was the Bishop of Rome from 2 January 533 to his death on 8 May 535. As a priest at St. Clement's Basilica, he endowed that church with gifts and commissioned stone carvings for it. Mercurius became the first pope to adopt a new papal name upon his elevation to the office. During his pontificate, John II notably removed Bishop Contumeliosus of Riez from his office, convened a council on the readmission of Arian clergy, and approved an edict of emperor Justinian, promulgating doctrine opposed by his predecessor, Pope Hormisdas. January 2, 533. Wiki link