The only historical record we have of the 1st century martyr, Saint Onesiphorus, is in the New Testament. In the Second Letter of Saint Paul to Timothy, Paul states: “May the Lord grant mercy to the family of Onesiphorus because he often gave me new heart and was not ashamed of my chains. But when he came to Rome, he promptly searched for me and found me. May the Lord grant him to find mercy from the Lord on that day. And you know very well the services he rendered in Ephesus.” (2 Timothy 1:16-18). Onesiphorus is again mentioned in Chapter 4, Verse 19 when Paul sends greetings to Prisca, Aquila, and Onesiphorus’ family.
Onesiphorus was a native of Ephesus and it is very likely that he was converted and/or baptized by Saint Paul himself. Obviously, his entire household converted along with him.
Onesiphorus traveled from Ephesus to Rome when he learned that Paul had been placed in chains. It is thought the two spent quite a bit of time together and that Paul considered him a dear friend.
Although Onesiphorus is venerated as a martyr, very little is known about his death. According to tradition, the Roman Emperor ordered his execution on a place called the Hellespont. Onesiphorus was torn apart by wild horses along with another Christian named Porphyrius. This Porphyrius should not be confused with Saint Porphyrius, the 4th century bishop of Gaza. The exact date of Onesiphorus’ death is unknown. However, Paul was put in chains around the year 60 and executed in 67. This would place Onesiphorus’ death around the year 65.
Because the mention made of Onesiphorus in the Letter to Timothy is in the past tense, it is widely felt that he had already been martyred when Paul wrote the letter. This would explain why Paul prays for the saint’s family and why he seems to eulogize him. Also, 2 Timothy 1:18 can be considered evidence that the Christians of the Early Church did indeed pray for the dead. It is widely felt that when Paul says “May the Lord grant him to find mercy from the Lord on that day”, he is referring to the Day of Judgment.
Although Saint Onesiphorus is still revered, his memorial is usually overridden by those of other, more popular saints. Historically, however, his feast day is September 6.
Sources: Butler’s Lives of the Saints
The New Testament, New American Translation