When a group of the apostacized, known as the Lapsi, refused to do penance, Marcellus refused to allow their return to the Church. The Lapsi had a bit of political pull, and some members caused such civil disruption that emperor Maxentius exiled the Pope in order to settle the matter. Legend says that Marcellus was forced to work as a stable slave as punishment, but this appears to be fiction, however we do know that he died of the terrible conditions he suffered in exile, and is considered a martyr because of that.
He was initially buried in the cemetery of Saint Priscilla in Rome, but his relics were later transferred to beneath the altar of San Marcello al Corso Church in Rome where they remain today.
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