On Friday, Christians around the world commemorate with prayers and fasting the death of Jesus Christ, three days before the arrival of Easter and the hope of the Resurrection.

The church calls on believers to solemnly reflect on the pain and suffering of Jesus of Nazareth, particularly beginning at 3 p.m. when it is believed Jesus died as he hung on a cross outside the city of Jerusalem.

While the Bible gives agonizing details of the crucifixion of Jesus, what do we know about what happens to a body undergoing this sadistic method of execution?

How does crucifixion kill you?

First, the history

Crucifixion is a gruesome mode of execution, and that’s why the Romans in Jesus’ day used it. A method of control and intimidation, Roman authorities used crucifixion to rid their cities of slaves, heinous criminals and, most important to the empire, insurgents.

Crucifixion was likely first used in what is modern day Iran. The vicious method of eliminating one’s enemies spread throughout the ancient world to Greece where Alexander the Great was known to have used it.

From there, the Romans adopted the practice and elevated it to a level that was unprecedented – at one point crucifying 500 people a day. It was practiced from the 6th century BC until the 4th century AD. The Roman emperor Constantine I banned the practice in 337 AD.

Why use crucifixion?

The  Romans did not lack for ways to kill their enemies, but crucifixion allowed for two things – humiliation and a slow, painful death. The punishment was a method of intimidation that the Romans raised to an art form.

One Roman historian wrote of an event that saw 2,000 crucified on one day for the amusement of an emperor.

The process

Crucifixion followed a bloody script of sorts that  maximized the suffering and prolonged death. It began when the one being crucified was stripped of his clothing then beaten with a flagrum, a short-handled whip made with lengths of leather that had bone and iron balls woven into the strips.

The person was beaten savagely with the whip which tore flesh then muscle, weakening the victim through blood loss and shock. While the aim was to inflict maximum injury, that part of the process was not intended to kill.

After the beating -- where ribs were often broken from the repeated blows -- the victim would be forced to pick up and carry the beam of the cross he was to be hanged on.

Crucifixions were held outside of the city, and while the upright part of the cross, called the stripe, was permanently placed in the area the crucifixions took place, the crossbar, called the patibulum, had to be transported there. The patibulum usually weighed between 75 and 100 pounds.

We often see images of Jesus Christ nailed to a cross that is high above the  ground, but this likely isn’t a true representation of Roman crucifixions.

The first crucifixions had the victims suspended just above the ground so their feet would not touch holy ground. By the time the Romans were crucifying people, the crosses were probably from 7 to 9 feet tall.

Not all crosses were the familiar “t” shape we see depicted in art. Some resembled the letters “X” and “Y,” while some looked like an uppercase “T.” Some people, like the Apostle Peter, were crucified upside down on an inverted cross.

Some researchers say Jesus may have been crucified on a stake instead of a cross, which was another method of crucifixion.

While we read in the Bible of  Jesus’ hands and feet being nailed the cross, that wasn’t always the case, either. When the hands were attached to the cross, it was usually done with spikes being driven into the wrists, not the hands, to better support the weight of the victim. Most victims, according to the writing of historians of the day, had their hands tied to the cross with rope, their feet nailed into the sides near the bottom of the cross.

The victims knees would be bent at around 45 degrees before their feet were nailed to the cross. The position eventually makes it impossible to hold one’s self upright, and the person would begin sag on the cross. The body’s weight would eventually pull the shoulders out of socket,  thrusting the chest forward where it would become impossible to take in a breath.

It is written in the Bible that at one point Jesus was offered a drink of wine and a mild pain killer called gall or myrhh, and he declined it. The practice of offering those being crucified the drink  is documented  in other historical accounts. It was a service provided by a group of women from Jerusalem.

How do you die?

If you survived the shock and blood loss from the beating, then were able to carry the patibulum to the place where you were to be crucified, then lived through your feet and your hands having spikes driven into them, your final misery was just beginning.

There are many theories as to what kills you as you hang on a cross. From blood loss from the beating, to shock and dehydration, it could be any combination of the factors, scientists believe.

The Royal Society of Medicine in 2006 published an article that centered on Jesus' crucifixion, chronicling nine possible causes of death. And while suffocation from the weight of one's body dangling from a cross has long been believed to be the cause of death in crucifixion,  others think the process is a more complicated chain reaction of events.

The researchers from the RSM study believed death came to those crucified by one or more of the body’s failing processes.

The study suggested that as the person suspended on a cross struggles to breath, that lack of oxygen would trigger damage to tissue and veins causing blood to leak into the lungs and the heart. The lungs would stiffen and the heart become constricted from the pressure, making it difficult, then impossible to pump blood throughout the body. The lack of oxygenated blood would eventually cause each body system to fail and death would follow.

It could take hours, or, in some cases, days, but it was only a matter of time before death would come.

In the biblical accounts of Jesus’ death, the process took six hours, and, in the end, he cried out to God.

Matthew  27:50-51 "And Jesus cried out again with a loud voice, and yielded up the ghost. And behold, the veil of the temple was torn in two from top to bottom; and the earth shook and the rocks were split.…"

Sources: Gizmodo; Believe.com; NIM; The Guardian