There is actually an anti-pope who is considered a saint. St. Hipollytus of Rome declared himself Pope in opposition to the current Pontiff, whom he was in disagreement with concerning how to handle the modalist heresy. He was an anti-pope for 19 years. A new Roman emperor eventually captured both Hipollytus and the real Pope, St. Pontian, and were sent to the mines in Sardinia. During imprisonment, Hipollytus rejected his claim on the papacy and sought the forgiveness of Pontian. Both worked in the mines, ministering to the other prisoners until their deaths. Both saints share the same feast day and are always celebrated together to honor the friendship and companionship they exhibited during their ministry in prison.