The Pope was his enemy
He would later be arrested and soon would be astounded to find the Pope incarcerated there with him.
Pontian, the only pope of that name, had been the latest of those against whom Hippolytus had rebelled.
Pontian had actually resigned from the papacy after he had been arrested by the Emperor in 235 so that the Church would have a free shepherd, but now he saw an opportunity to bring a lost sheep back into the fold.
In that terrible place, Pontian reconciled Hippolytus to the Church and in that terrible place they both died: martyrs for the one true faith of Christ.
Their memory is celebrated on this day.
(from an earlier post)