The death of Jesus Christ has been a source of fascination for millennia. It was His horrific execution that led to the birth of the largest and most influential religion on Earth and shaped history for centuries. Billions of Christians across the ages have talked about how Jesus was killed by crucifixion and died on the cross for their sins. As medicine developed and the actual use of crucifixion died out, doctors and scholars began to want more information about Jesus’ death than simply that He died on the cross. Yes, He was crucified, but the actual act of nailing someone to a cross is not inherently life-threatening. That was why the Romans chose it. People could live for multiple days on the cross if the Romans were careful about how they went about the actual crucifixion. Jesus, the most famous crucifixion victim of all, died in a handful of hours. So, what actually killed Jesus? How did He really die?

Thankfully for the populace, a full Roman crucifixion has not been done since the 4th century. Unfortunately for scholars, that makes information about this horrific method of execution harder to come by. That said, Rome is known for having kept excellent records for its time. As a result, crucifixion is better understood than most extreme punishments from the ancient world. Existing records of “lingchi,” for example, are hard to come by and often seem medically impossible. Similarly, scholars are unsure if descriptions of the Blood Eagle, the brutal method of execution made infamous by the TV show “Vikings,” were meant to be poetic and symbolic or to be taken literally. There exists enough information about Roman crucifixion, on the other hand, that it would be easy to recreate it and get it right.

Knowledge about Roman crucifixion is not the same thing as knowing what part of the horrific process eventually cost Jesus His life. It is well-known that no one survived a full Roman crucifixion. That said, Rome made sure the actual process of dying was drawn out long enough that any number of things could have been the technical cause of death, but which was the cause of Jesus’ death?

For a crucifixion victim, Jesus died fast. The time from His conviction under Pilate to His death lasted less than a full day. Some crucified men lasted multiple times that amount on the cross not including the time involved for the scourging and long march to Golgotha. Those who hung on the cross for days or even overnight were not often killed by their wounds. Instead, they died of dehydration or exposure. When used as a cause of death, “exposure” is something of a catch all term for all sorts of ways of dying due to prolonged time out in elements that might not otherwise be fatal. People who died of exposure usually technically were killed by hypothermia, heat stroke, frostbite or sunburn. When a person is trapped outside, death from exposure can occur at any temperature above 80 degrees Fahrenheit or below 60 degrees Fahrenheit. Throw in the trauma of a crucifixion, and it would be easy for a man to perish in the chilly Israeli nights or beneath the Judean sun. Similarly, dehydration would set in rapidly when a person was already dealing with heavy blood loss. It would likely not kill, however, nearly quickly enough to be the cause of Jesus’ death.

The most commonly suggested cause of death for Jesus is suffocation. This would be one of the most likely causes of a swift death on the cross. The way crucifixion victims were hung stretched out the ribcage and the lungs. This prevented the condemned from exhaling effectively. The struggle to breathe would only become more difficult as the weight of a person’s body slowly dislocated their shoulders. In order to combat this, many Roman crosses were made with a small seat called a sedile that would keep some of the weight off a person’s chest and allowed them to breathe somewhat normally. When Rome wanted a person to suffer on the cross for a long time, they would use a cross with a sedile and nail the person’s feet in such a way that they could support their own weight. Based on the most common descriptions of how Christ was hung from the cross, Rome wanted to kill Him quickly as His feet were not positioned in a way that would help support His weight. This is further supported by the fact that the Roman soldiers broke the legs of the robbers hung beside Christ. Without support from their legs, they would suffocate quickly. 

Suffocation fits with the speed of Christ’s death, but not with His actions shortly before He breathed His last. The gospels describe Jesus as holding lucid conversations and crying out loudly shortly before He died. Neither of these would be possible for someone fighting for every breath of air they could find. Christ also knew when His time had come. Someone who suffocated would slowly lose consciousness before dying, not die suddenly.

Perhaps the most convincing but least discussed theory for the cause of Christ’s death is that the fatal blow was actually struck before He was nailed to the cross. Christian tradition states that during Jesus’ walk to Golgotha, He fell to the ground. The Bible never explicitly says He did, but it is a reasonable assumption and was likely a common occurrence during the march to a crucifixion site as blood loss and pain from the scourging would have made carrying the 100 pound crossbeam extremely difficult. 

When Jesus fell, it is almost certain that He had no way to catch Himself. Roman soldiers would tie crucifixion victims’ hands to the crossbeam before marching them through the city to the crucifixion site where the nails would be driven in. This means that when Jesus fell, both His body weight and the weight of the crossbeam fell directly on His chest. This is the sort of impact that occurs in car crashes, and it can be lethal even with modern medical intervention. In such a fall or collision, the heart slams into the sternum, bruising the actual organ. That bruise is a weak point in the heart muscle. With every beat of the heart, that weak point swells to form an aneurism. When that aneurism bursts, death follows rapidly. The more stress that the heart is under, the more likely the aneurism is to burst, and few things are harder on the heart than a Roman crucifixion. 

Hanging on the cross, Christ would have been able to feel the aneurism give way and call out His final words. The blood from the burst heart would be trapped in the pericardium, a fluid filled sack that surrounds the heart. When the spear pierced Jesus’ side, this mix of fluid and blood would have rushed out and appeared as “water and blood.”

Different theories about what killed Jesus have different levels of evidence supporting them, but unless someone invents a time machine and is able to do an autopsy on Jesus Himself, the question is likely to remain unanswered. What the fatal blow was, however, is a fact of limited real importance. Crucifixion had dozens of ways to kill, but they all came as a result of being nailed to a cross. Perhaps it is better that the cause of Jesus’ death is left as simply reading “crucifixion.” The cross itself may not have been lethal, but there is no doubt that is what killed Him. As such, saying He died on the cross gives a better explanation for His death since it contains more pieces of the puzzle and better demonstrates exactly how horrific of a death Christ suffered for those who were least deserving of His sacrifice.