There is a two year gap between Popes due to the unrelenting persecution of Christians during the reign of Emperor Diocletian. A new Emperor named Maxentius came into power and relaxed the anti-Christian laws. The clouds were parting for Christianity and those that had lapsed and renounced their faith for fear of their lives wanted to come back to the Church. Pope Marcellus was one of the Christians that held firm during the persecution and he was in no mood to facilitate a way for apostates to come back into the Church. He demanded severe public penances and tension between Christians soon erupted into riots and bloodshed. The Emperor of Rome,never a friend to Christians,actually had to step in and order the Pope to lighten up on his people. How insane is that? Pope Marcellus refused and he was eventually banished from Rome in 309. He died of unknown causes that same year. His feast day is January 16th and his relics are kept under the altar of the Church of San Marcello al Corso in Rome.