On August 13 the Catholic Church celebrates the feast of Sts. Pontian and Hippolytus, two of the most interesting figures in all of papal history.

Pontian (230-35) was the first pope to have abdicated, or resigned, his office, and Hippolytus (d. about 236) was not only the first of 39 antipopes in the history of the Church but also the only antipope to be recognized as a saint, with a feast on the General Roman Calendar. Both died on the island of Sardinia, to which they had been deported.

The five-year pontificate of Pontian had been for the most part peaceful because of the policy of toleration adopted by the emperor Severus. The words "for the most part" are a necessary qualification because Pontian did have to deal with the presence of Hippolytus and his followers.

Hippolytus had refused to accept the election of Callistus as pope in 217. Callistus had been Pope Zephrynus's (198/9-217) deacon, with supervisory authority over the clergy of Rome and over the official cemetery on the Appian Way (now known as the catacombs of San Callisto).

Because of Zephrynus's intellectual and administrative limitations, Callistus exercised enormous influence over him and the local church of Rome. When Callistus was elected to succeed Zephrynus, Hippolytus, a leading Roman priest who had been a severe critic of both Pope Zephrynus and his deacon, sought and received election as Bishop of Rome from a schismatic group.

Callistus' five-year pontificate was marked by constant battles with Hippolytus and his faction, but the conflict subsided during the pontificate of Callistus's successor, Urban I (222-30). That was also generally the case during Pontian's pontificate, in the years immediately following Urban's reign.

In March of the year 235, however, the emperor Severus was succeeded by Maximinus Thrax, who abandoned his predecessor's policy of toleration and launched a violent campaign against Christian leaders. Pontian, as the Bishop of Rome, was the biggest and most obvious target.

The new emperor arrested not only Pontian but also Hippolytus, the other claimant to the Chair of Peter. Both men were imprisoned in Rome and then exiled to Sardinia to work in the mines. Since deportation was usually for life and few survived it, Pontian abdicated to allow a successor to assume pastoral leadership of the Roman church as soon as possible.

According to the fourth-century Liberian Catalogue, Pontian abdicated on September 28, 235, the first precisely recorded date in papal history.

Not surprisingly, neither Pontian nor Hippolytus survived the harsh treatment and conditions on Sardinia, which was known as the "island of death" for good reason. Pontian died less than a month after his abdication.

Some historians have suggested that both men were reconciled while in prison in Rome or while in exile on Sardinia, and that when Pontian resigned as Bishop of Rome, Hippolytus also renounced his claim to the papacy and urged his followers to end their schism. Unity was thereby restored to the Roman church.

Their bodies were brought back to Rome by Pope Fabian (236-50) in 236 or 237. Pontian was buried in the newly completed papal crypt in the aforementioned catacombs of Callistus on the Appian Way on August 13 (his feast day, along with Hippolytus). On the same day, the remains of Hippolytus were buried on the Via Tiburtina in a cemetery which thereafter bore his name.

Hippolytus had been born in the Greek-speaking East, unlike Pontian who was a Roman by birth, and was a product of Greek philosophical culture. He came to Rome and was ordained during the pontificate of Victor I (189-98). He was also the author of a number of works of theology and biblical studies, and his writings are an important source for liturgical scholars.

But his general approach to pastoral issues would not commend him to many Catholics today. Known as a rigorist, he strongly opposed what he called "laxity" toward sinners and insisted that the validity of the sacraments depends upon the sanctity of those who administer them --- a position unequivocally rejected by the Church because of its pastorally chaotic implications.

If Hippolytus' views were to have become official church teaching, we would never know whether a sacrament had been validly administered. No one can read the state of soul of another person, including that of the priest-celebrant. Nor of a bishop ordaining a group of priests. Would their ordination have been valid? Would their subsequent Masses and other sacraments be validly celebrated and administered?

The feast of Hippolytus alone is celebrated in the East on January 30. Significantly, in the Russian Orthodox calendar he is identified as "pope of Rome."

Fr. Richard McBrien is the Crowley-O'Brien Professor of Theology at the University of Notre Dame.