As kind as Severus might have been to the Christians, his successor Maximus Thrax persecuted them. Although Maximus was not a religious man himself, he despised Severus and intended to reverse any attitude to which Severus might have been disposed. He therefore decreed that leaders of the Church be singled out and banished to the labor mines of Sardinia, the famous "Island of Death."
Pontian, a Roman and son of Calpurnius, had enjoyed a peaceful reign over the Roman Church during Severus' time, but soon found himself among the first victims of this new emperor. Rounded up with the antipope Hippolytus, Pontian was deported to the labor mines. Since deportation was a life sentence which few survived, Pontian felt obligated to abdicate so that a successor might quickly preside over the Holy See. He is the first pope known to have abdicated.
While imprisoned, Hippolytus reconciled his differences with Pontian and even ordered his followers to bring themselves back to the Church. Before he succumbed to the harsh treatment of the mines, Hippolytus became a true confessor of Christ.
Pontian, in the mines only two months, was brutally beaten to death by his jailers. His body, with that of Hippolytus, was returned to Rome approximately a year later, during the pontificate of Fabian. He was buried in the cemetery of Calixtus and was rightfully honored by the Church as a martyr.
~excerpted from The Popes: A Papal History, J.V. Bartlett.