The twelve men that Jesus called to be his apostles were about as motley a band as ever assembled. A few were so unremarkable that the Bible doesn't even bother to mention their profession, including those who were fishermen and one who was a despised tax collector. During the three years they followed Jesus during his earthly ministry, they continually exhibited an inability to understand even the simplest of parables, fought among themselves over who was the greatest in the group, and ultimately abandoned him at his arrest and crucifixion. By all logic, their actions should have spelled the end of Christianity before it even began.
Then came the resurrection, Pentecost, and a complete change in all of them. They spread out across the known world proclaiming the gospel to everyone they encountered, often despite intense persecution. And their deaths stand as some of the greatest proof that the resurrection is, in fact, genuine.
There have been many followers throughout history who died for the leader of a religious movement (in our time this has often happened, tragically, through mass suicide), but the deaths of the apostles fall into a different category altogether. Only John passed away naturally of the eleven original apostles who were present at Pentecost (Judas committed suicide after betraying Jesus).
Just as the bible is not very clear about the profession or other details of the apostles, the same goes for the way most of them have passed away. Theologists have researched many old texts to come to certain assumptions about how the apostles may have passed away. The other eleven perished in the following ways:
Peter and Paul were both martyred in Rome about 66 AD, during the persecution under Emperor Nero. Paul was beheaded. Peter was crucified, upside down at his request, since he did not feel he was worthy to die in the same manner as his Lord.
Andrew went to the "land of the man-eaters," in what is now the Soviet Union. Christians there claim him as the first to bring the gospel to their land. He also preached in Asia Minor, modern-day Turkey, and in Greece, where he is said to have been crucified.
Thomas was probably most active in the area east of Syria. Tradition has him preaching as far east as India, where the ancient Marthoma Christians revere him as their founder. They claim that he died there when pierced through with the spears of four soldiers.
Philip possibly had a powerful ministry in Carthage in North Africa and then in Asia Minor, where he converted the wife of a Roman proconsul. In retaliation the proconsul had Philip arrested and cruelly put to death.
Matthew the tax collector and writer of a Gospel ministered in Persia and Ethiopia. Some of the oldest reports say he was not martyred, while others say he was stabbed to death in Ethiopia.
Bartholomew had widespread missionary travels attributed to him by tradition: to India with Thomas, back to Armenia, and also to Ethiopia and Southern Arabia. There are various accounts of how he met his death as a martyr for the gospel.
James the son of Alpheus is one of at least three James referred to in the New Testament. There is some confusion as to which is which, but this James is reckoned to have ministered in Syria. The Jewish historian Josephus reported that he was stoned and then clubbed to death.
Simon the Zealot so the story goes, ministered in Persia and was killed after refusing to sacrifice to the sun god.
Matthias the apostle chose to replace Judas. Tradition sends him to Syria with Andrew and to death by burning.
Both the violent nature of these men’s deaths and the fact that they died at different times and in different parts of the Roman Empire is important. It is feasible that one or two of them may have been insane enough to die in order to maintain the tale of the resurrection if they realized it was a lie, which they would have known if they had either taken Jesus' body or had not personally witnessed it.
However, it is inconceivable that 10 of them would have experienced torturous deaths, utterly apart from the others by years and hundreds or thousands of kilometres, for a deception they were aware to be a lie.